Researcher Database

Yutaka Watanuki
Faculty of Fisheries Sciences Marine Bioresource and Environmental Science Marine Bioresource Science
Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Fisheries Sciences Marine Bioresource and Environmental Science Marine Bioresource Science

Job Title

  • Professor

J-Global ID

Research Interests

  • 海洋汚染モニタリング   海洋保全   バイオロギング   動物生態学   海洋生態学   marine Ecology   Animal Ecology   

Research Areas

  • Life sciences / Ecology and environmental science
  • Environmental science/Agricultural science / Biological resource conservation

Academic & Professional Experience

  • 2014/04 - Today Hokkaido University Faculty of Fisheries Sciences Professor
  • 2007/04 - 2014/03 Hokkaido University Faculty of Fisheries Sciences Associate Professor
  • 2003/04 - 2007/03 Hokkaido University Graduate School of Fisheries Sciences Associate Professor
  • 1997/04 - 2003/03 Hokkaido University Graduate School of Agriculture Associate Professor
  • 1993/10 - 1997/03 Hokkaido University Faculty of Agriculture Assistant Professor
  • 1987/12 - 1993/09 National Institute of Polar Research Biology Assistant Professor
  • 1987/04 - 1987/11 日本学術振興会 特別研究員

Education

  • 1983/04 - 1987/09  北海道大学大学院
  • 1981/04 - 1983/03  北海道大学大学院
  • 1978/04 - 1981/03  Hokkaido University  Faculty of Agriculture
  • 1977/04 - 1978/03  Hokkaido University

Association Memberships

  • 日本水産海洋学会   THE OCEANOGRAPHIC SOCIETY OF JAPAN   WILDLIFE CONSERVATION SOCIETY   Pacific Seabird Group   Ecological Society of Japan   American Ornithological Society   North Pacific Marine Science Organization   Ethological Society of Japan   Japanese Ornithological Society   

Research Activities

Published Papers

  • Consumption of juvenile chum salmon by a seabird species during early sea life
    Jumpei OKADO, Yosuke KOSHINO, Hideaki KUDO, Yutaka WATANUKI
    Fisheries Research 222 (105415) 1 - 7 2020 [Refereed][Not invited]
  • In vivo accumulation of plastics-derived chemicals into seabird tissues
    Kosuke Tanaka, Yutaka Watanuki, Hideshige Takada, Mayumi Ishizuka, Rei Yamashita, Mami Kazama, Nagako Hiki, Fumika Kashiwada, Kaoruko Mizukawa, Hazuki Mizukawa, David Hyrenbach, Michelle Hester, Yoshinori Ikenaka, Shouta M, M. Nakayama
    Current Biology 30 (4) 723 - 728.e3 2020/01 [Refereed][Not invited]
  • Nishizawa, B, N. Kanna, Y. Abe, Y. Ohashi, D. Sakakibara, I. Asaji, S. Sugiyama, A. Yamaguchi, Y. Watanuki
    ICES Journal of Marine Science fsz213 2019/12 [Refereed][Not invited]
  • Determination of on-water and feeding activities of Black-footed Albatrosses using acceleration and images
    Shota Tsukamoto, Bungo Nishizawa, Fumio Sato, Naoki Tomita, Yutaka Watanuki
    Japanese Journal of Ornithology 68 29 - 41 2019/04 [Refereed][Not invited]
  • Transfer of additives from ingested plastics to seabirds and their accumulation in the tissue
    Takada Hideshige, Tanaka Kosuke, Yamashita Rei, Watanuki Yutaka
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 257 0065-7727 2019/03/31 [Refereed][Not invited]
  • 北海道大黒島における海鳥の現状
    大門純平, 伊藤元裕, 綿貫豊
    山階鳥類学雑誌 51 95 - 104 2019 [Refereed][Not invited]
  • Masayuki Senzaki, Akira Terui, Naoki Tomita, Fumio Sato, Yoshihiro Fukuda, Yoshihiro Kataoka, Yutaka Watanuki
    Bird Conservation International 0959-2709 2019/01 [Refereed][Not invited]
     
    © 2019 BirdLife International. Global seabird populations are in decline, with nearly half of all seabird species currently in an extinction crisis. Understanding long-term seabird population trends is an essential first step to inform conservation actions. In this study, we assembled historical breeding records of seabirds throughout the Japanese archipelago and quantified the long-term population trends of 10 major breeding seabird species using a hierarchical Bayesian state-space model. The model revealed that six species had increasing or no detectable trends (Short-tailed Albatross Phoebastria albatrus, Leach's Storm Petrel Oceanodroma leucorhoa, Pelagic Cormorant Phalacrocorax pelagicus, Japanese Cormorant Phalacrocorax capillatus, Spectacled Guillemot Cepphus carbo, and Rhinoceros Auklet Cerorhinca monocerata). However, decreasing trends were found not only in nationally threatened species (Common Murre Uria aalge, and Tufted Puffin Fratercula cirrhata) but also common species that are often described as abundant (Black-tailed Gull Larus crassirostris and Slaty-backed Gull Larus schistisagus). These declining species have declined to 3-35% of baseline levels over the past 30 years. This study provides the first evidence of long-term declines in common and widespread seabirds in Japan.
  • Kazama Kentaro, Harada Tomoko, Deguchi Tomohiro, Suzuki Hajime, Watanuki Yutaka
    ORNITHOLOGICAL SCIENCE 18 (1) 27 - 37 1347-0558 2019/01 [Refereed][Not invited]
  • N. Kokubun, A. Takahashi, R. Paredes, R. C. Young, N. N. Sato, T. Yamamoto, D. M. Kikuchi, E. V. Kitaiskaia, M. Ito, Y. Watanuki, A. P. Will, R. Lauth, M. D. Romano, A. S. Kitaysky
    Marine Ecology Progress Series 593 195 - 208 0171-8630 2018/04 [Refereed][Not invited]
     
    © 2018 Inter-Research. Warm oceanographic conditions of the continental shelf regions in the southeastern Bering Sea are associated with drastic increases in the abundance of juvenile walleye pollock Gadus chalcogrammus at shallow depths. We hypothesized that thick-billed murres Uria lomvia would benefit from these warm conditions by taking advantage of such an abundant prey resource available near their breeding colonies. We compiled a large dataset on the foraging behavior and nutritional state of murres breeding on St. George Island between 2003 and 2015. Murres foraged mostly on the continental shelf in warm years, but foraged in both on-shelf and off-shelf habitats in cold years. Shifts in foraging locations were associated with changes in diving depths. Nighttime foraging and daily diving effort increased during cold years, suggesting murres had to work more to obtain food under cold compared to warm conditions. Chick diets shifted from squid and benthic fishes in cold years to juvenile pollock in warm years. Foraging trip duration and reproductive success of birds were not affected by shifting oceanographic conditions, suggesting that murres behaviorally mediated the effects of inter-annual climate variability on their reproduction. However, this 'behavioral buffering' had associated costs, reflected in higher corticosterone concentrations in the blood of murres in cold compared to warm years, indicating that breeding birds incurred higher levels of nutritional stress under cold conditions. Our multiyear integrative study provides support that warmer conditions on the continental shelf might benefit piscivorous seabirds due to an increase in the availability of juvenile walleye pollock in the southeastern Bering Sea.
  • Streaked sheawater Calonectris leucomelas moonlight avoidance in response to low aerial predation pressure, and effects of wind speed and direction on colony attendance.
    Van Tatenhove A, Fayet A, Watanuki Y, Yoda K, Shoji A
    Mar Ornithol 46 177 - 185 2018 [Refereed][Not invited]
  • Biotransport of metallic trace elements from marine to terrestrial ecosystems by seabirds.
    Shoji A, Elliott KH, Aris-Brosou S, Mizukawa H, Nakayama SMM, Ikenaka Y, M. Ishizuka M, Kuwae T, K. Watanabe, Gonzalez JE, Y. Watanuki Y
    Environ Toxicol Chem 2018 [Refereed][Not invited]
  • Global monitoring of persistent organic pollutants (POPs) using seabird preen gland oil.
    Yamashita R, Hideshige Takada H, Nakazawa A, Takahashi A, Ito M, Yamamoto T, Watanabe YY, Kokubun N, Sato K, Wanless S, Daunt F, Hyrenbach D, Hester M, Deguchi T, Nishizawa B, Shoji A, Watanuki Y
    Arch Environ Contam Toxicol 75 545 - 556 2018 [Refereed][Not invited]
  • Seabird densities and species and hydrographic features across Amchitka Pass, Aleutian Islands.
    Nishizawa B, Ohnishi H, Watanuki Y
    Fisheries Science 2018 [Refereed][Not invited]
  • Albatross chicks reveal interactions of adults with artisanal longline fisheries within a short range.
    Thiebot J-B, Nishizawa B, Sato F, Tomita N, Watanuki Y
    159 935 - 944 2018 [Refereed][Not invited]
  • Male and female Black-tailed Gulls feed on the same prey species but use different feeding habitats
    Kazama K, Nishizawa B, Tsukamoto S, Gonzalez JE, Kazama MT, Watanuki Y
    J Ornithol 159 923 - 934 2018 [Refereed][Not invited]
  • 小黒亮, 平田和彦, 綿貫豊
    日本鳥学会誌 67 101 - 107 2018 [Refereed][Not invited]
  • 外洋表層の生態学的・生物学的重要海域特定への海鳥の利用
    綿貫豊, 山本裕, 佐藤真弓, 山本誉士, 依田憲, 高橋晃周
    日本生態学会誌 68 81 - 99 2018 [Refereed][Not invited]
  • Factors affecting the importance of myctophids in the diet of the world’s seabirds.
    Watanuki Y, Thiebot J-B
    Mar Biol 165 2018 [Refereed][Not invited]
  • Global phenological insensitivity to shifting ocean temperatures among seabirds.
    Keogan K, Daunt F, Wanless S, Phillips R, Walling C, Agnew P, Ainley D, Anker-Nilssen T, Ballard G, Barrett R, Barton K, Bech C, Becker PH, Berglund P-A, Bollache L, Bond A, Bouwhuis S, Bradley R, Burr Z, Camphuysen C, Catry P, Chiaradia A, Christensen-Dalsgaard S, Cuthbert R, Dehnhard N, Descamps S, Diamond A, Divoky G, Drummond H, Dugger K, Dunn M, Emmerson L, Erikstad KE, Fort J, Fraser W, Genovart M, Gilg O, Solís J, Granadeiro JP, Grémillet D, Hansen J, Hanssen SA, Harris M, Hedd A, Hinke J, Igual J-M, Jahncke J, Jones I, Kappes P, Lang J, Langset M, Lescroël A, Lorentsen S, Lyver P, Mallory M, Moe B, Montevecchi W, Monticelli D, Mostello C, Newell M, Nicholson L, Nisbet I, Olsson O, Oro D, Pattison V, Poisbleau M, Pyk T, Quintana F, Ramos J, Ramos R, Reiertsen T, Rodríguez C, Ryan P, Sanz-Aguilar A, Schmidt N, Shannon P, Sittler B, Southwell C, Surman C, Svagelj W, Trivelpiece W, Warzybok P, Watanuki Y, Weimerskirch H, Wilson P, Wood A, Phillimore A, Lewis S
    Nature Climate Change 8 313 - 318 2018 [Refereed][Not invited]
  • Rhinoceros Auklet pair-mates migrate independently but synchronize their foraging activity during the pre-laying period.
    Kubo A, Takahashi A, Thiebot J-B, Watanuki Y
    Ibis 180 832 - 845 2018 [Refereed][Not invited]
  • Albatross-borne loggers show feeding on probable post-spawning deep-sea squids: implications for the study of squid distributions.
    Nishizawa B, Sugawara T, Young LC, Vanderwerf EA, Yoda K, Watanuki Y
    Mar Ecol Prog Ser 592 (257) 265  2018 [Refereed][Not invited]
  • Chihiro Ishii, Yoshinori Ikenaka, Shouta M M Nakayama, Hazuki Mizukawa, Yared Beyene Yohannes, Yutaka Watanuki, Masaaki Fukuwaka, Mayumi Ishizuka
    The Journal of veterinary medical science 79 (4) 807 - 814 0916-7250 2017/04/20 [Refereed][Not invited]
     
    Seabirds are marine top predators and accumulate high levels of metals and metalloids in their tissues. Contamination by metals in the highly productive offshore region has become a matter of public concern. It is home to 80% of the seabird population in the U.S.A., 95% of northern fur seals (Callorhinus ursinus), and major populations of Steller sea lions (Eumetopias jubatus), walruses (Odobenus rosmarus) and whales. Here, the concentrations of eight heavy metals (Hg, Cd, Cr, Co, Ni, Cu, Zn and Pb) and a metalloid (As) in the liver and kidneys of the northern fulmar (Fulmarus glacialis), thick-billed murre (Uria lomvia), short-tailed shearwater (Puffinus tenuirostris), tufted puffin (Fratercula cirrhata) and horned puffin (Fratercula corniculata) collected in the Bering Sea were measured. As proxies of trophic level and habitat, nitrogen (δ15N) and carbon (δ13C) stable isotope ratios of breast muscles were also measured. Hepatic Hg concentration was high in northern fulmar, whereas Cd level was high in tufted puffin and northern fulmar. The Hg concentration and δ15N value were positively correlated across individual birds, suggesting that Hg uptake was linked to the trophic status of consumed prey. Furthermore, Hg concentration in our study was higher than those of the same species of seabirds collected in 1990.
  • Bungo Nishizawa, Kohei Matsuno, Elizabeth A. Labunski, Kathy J. Kuletz, Atsushi Yamaguchi, Yutaka Watanuki
    BIOGEOSCIENCES 14 (1) 203 - 214 1726-4170 2017/01 [Refereed][Not invited]
     
    The short-tailed shearwater (Ardenna tenuirostris) is one of the abundant marine top predators in the Pacific; this seabird spends its non-breeding period in the northern North Pacific during May-October and many visit the southern Chukchi Sea in August-September. We examined potential factors affecting this seasonal pattern of distribution by counting short-tailed shearwaters from boats. Their main prey, krill, was sampled by net tows in the southeastern Bering Sea/Aleutian Islands and in the Bering Strait/southern Chukchi Sea. Short-tailed shearwaters were mainly distributed in the southeastern Bering Sea/Aleutian Islands (60 +/- 473 birds km(-2)) in July 2013, and in the Bering Strait/southern Chukchi Sea (19 +/- 91 birds km(-2)) in September 2012. In the Bering Strait/southern Chukchi Sea, krill size was greater in September 2012 (9.6 +/- 5.0 mm in total length) than in July 2013 (1.9 +/- 1.2 mm). Within the Bering Strait/southern Chukchi Sea in September 2012, short-tailed shearwaters occurred more frequently in cells (50 +/- 50 km) where large-sized krill were more abundant. These findings, and information previously collected in other studies, suggest that the seasonal northward movement of short-tailed shearwaters might be associated with the seasonal increase in krill size in the Bering Strait/southern Chukchi Sea. We could not, however, rule out the possibility that large interannual variation in krill abundance might influence the seasonal distribution of shearwaters. This study highlights the importance of krill, which is advected from the Pacific, as an important prey of top predators in the Arctic marine ecosystem.
  • Hiroko Sasaki, Kohei Matsuno, Amane Fujiwara, Misaki Onuka, Atsushi Yamaguchi, Hiromichi Ueno, Yutaka Watanuki, Takashi Kikuchi
    BIOGEOSCIENCES 13 (15) 4555 - 4567 1726-4170 2016/08 [Refereed][Not invited]
     
    The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed habitat models explaining the spatial patterns of large and small Arctic and Pacific copepods separately. Copepods were sampled using NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle component analysis scores, satellite-derived timing of sea ice retreat, bottom depth and chlorophyll a concentration were integrated into generalized additive models as explanatory variables. The adequate models for all copepods exhibited clear continuous relationships between the abundance of copepods and the indexed water masses. Large Arctic copepods were abundant at stations where the bottom layer was saline; however they were scarce at stations where warm fresh water formed the upper layer. Small Arctic copepods were abundant at stations where the upper layer was warm and saline and the bottom layer was cold and highly saline. In contrast, Pacific copepods were abundant at stations where the Pacific-origin water mass was predominant (i.e. a warm, saline upper layer and saline and a highly saline bottom layer). All copepod groups showed a positive relationship with early sea ice retreat. Early sea ice retreat has been reported to initiate spring blooms in open water, allowing copepods to utilize more food while maintaining their high activity in warm water without sea ice and cold water. This finding indicates that early sea ice retreat has positive effects on the abundance of all copepod groups in the northern Bering and Chukchi seas, suggesting a change from a pelagic-benthic-type ecosystem to a pelagic-pelagic type.
  • Yoshinari Yonehara, Yusuke Goto, Ken Yoda, Yutaka Watanuki, Lindsay C. Young, Henri Weimerskirch, Charles-Andre Bost, Katsufumi Sato
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 113 (32) 9039 - 9044 0027-8424 2016/08 [Refereed][Not invited]
     
    Ocean surface winds are an essential factor in understanding the physical interactions between the atmosphere and the ocean. Surface winds measured by satellite scatterometers and buoys cover most of the global ocean; however, there are still spatial and temporal gaps and finer-scale variations of wind that may be overlooked, particularly in coastal areas. Here, we show that flight paths of soaring seabirds can be used to estimate fine-scale (every 5 min, similar to 5 km) ocean surface winds. Fine-scale global positioning system (GPS) positional data revealed that soaring seabirds flew tortuously and ground speed fluctuated presumably due to tail winds and head winds. Taking advantage of the ground speed difference in relation to flight direction, we reliably estimated wind speed and direction experienced by the birds. These bird-based wind velocities were significantly correlated with wind velocities estimated by satellite-borne scatterometers. Furthermore, extensive travel distances and flight duration of the seabirds enabled a wide range of high-resolution wind observations, especially in coastal areas. Our study suggests that seabirds provide a platform from which to measure ocean surface winds, potentially complementing conventional wind measurements by covering spatial and temporal measurement gaps.
  • Daisuke Ochi, Kei Matsumoto, Nariko Oka, Tomohiro Deguchi, Katsufumi Sato, Takashi P. Satoh, Fumihito Muto, Yutaka Watanuki
    ORNITHOLOGICAL SCIENCE 15 (2) 213 - 225 1347-0558 2016/07 [Refereed][Not invited]
     
    Parent Procellariiformes alternate between long-range foraging trips to feed in distant productive marine areas and short-range trips to feed in less productive areas around their breeding colony. Foraging trip duration, diet, energy expenditure, and chick growth of Streaked Shearwaters Calonectris leucomelas were compared between two colonies, one on Mikura Island located in the warm and less productive waters of the Kuroshio current, and the other on Sangan Island located in the cold and more productive waters of the Kuroshio/Oyashio transition zone. Parent shearwaters breeding on Mikura alternated between short (<= 3 days) trips to Kuroshio waters in order to provision their chicks and long (>3 days) trips to the cold Oyashio region in order to accumulate energy reserves for themselves. Shearwaters breeding on Sangan mainly took short trips (<= 2 days) to the nearby Kuroshio/Oyashio transition zone, but also took longer trips (>2 days) to the cold Oyashio region. Parent shearwaters breeding on Mikura, however, made more frequent long trips (24%) than those breeding on Sangan (9%). Parents at both colonies commonly brought Japanese Anchovy Engraulis japonica and Darkedged-wing Flyingfish Cypselurus hiraii for their young, while parents on Mikura also brought Pacific Saury Cololabis saira and stomach oil after long trips. Parents on Mikura delivered energy at a lower rate, resulting in lower chick growth rates and smaller fledging masses than on Sangan. Unlike other Procellariiformes seabirds, shearwater parents on Sangan accumulate their own body reserves even during the chick rearing period because of better foraging efficiency than on Mikura. This may indicate that chicks were satiated by the meals delivered to them allowing parents to utilize the remaining provisions for their own body reserves.
  • Tsubasa Nakano, Kohei Matsuno, Bungo Nishizawa, Yuka Iwahara, Yoko Mitani, Jun Yamamoto, Yasunori Sakurai, Yutaka Watanuki
    POLAR BIOLOGY 39 (6) 1081 - 1086 0722-4060 2016/06 [Refereed][Not invited]
     
    To understand trophic responses of polar cod Boreogadus saida (a key species in Arctic food webs) to changes in zooplankton and benthic invertebrate communities (prey), we compared its stomach contents and body condition between three regions with different environments: the northern Bering Sea (NB), southern Chukchi Sea (SC), and central Chukchi Sea (CC). Polar cod were sampled using a bottom trawl, and their potential prey species in the environment were sampled using a plankton net and a surface sediment sampler. Polar cod fed mainly on appendicularians in the NB and SC where copepods were the most abundant in the environment, while they fed on copepods, euphausiids, and gammarids in the CC where barnacle larvae were the most abundant species in plankton samples on average. The stomach fullness index of polar cod was higher in the NB and SC than CC, while their body condition index did not differ between these regions. The lower lipid content of appendicularians compared to other prey species is the most plausible explanation for this inconsistency.
  • Yutaka Watanuki, Ai Yamashita, Mayumi Ishizuka, Yoshinori Ikenaka, Shouta M. M. Nakayama, Chihiro Ishii, Takashi Yamamoto, Motohiro Ito, Tomohiro Kuwae, Philip N. Trathan
    MARINE ECOLOGY PROGRESS SERIES 546 263 - 269 0171-8630 2016/03 [Refereed][Not invited]
     
    We measured mercury concentration ([Hg]) and nitrogen stable isotope values (delta N-15) in tail feathers that were replaced during the non-breeding period of streaked shearwaters Calonectris leucomelas that bred on 3 islands in Japan. The birds' year-round movements were tracked and their breeding status was monitored. [Hg] was greater in males than in females, and was greatest in those birds spending their non-breeding period in the South China Sea (3.1 +/- 1.5 mu g g(-1) dry weight), moderate in birds in the Arafura Sea (1.5 +/- 0.7 mu g g(-1)), and lowest in birds in the Pacific Ocean north of New Guinea (0.8 +/- 0.4 mu g g(-1)). Adverse effects of feather [Hg] on breeding status were not observed. This regional variation in feather [Hg] might partly reflect differences in the intake of Hg between these non-breeding areas in addition to accumulation during the late breeding period and the southward migration period.
  • Yukihisa Kogure, Katsufumi Sato, Yutaka Watanuki, Sarah Wanless, Francis Daunt
    JOURNAL OF EXPERIMENTAL BIOLOGY 219 (3) 311 - 318 0022-0949 2016/02 [Refereed][Not invited]
     
    Aerodynamics results in two characteristic speeds of flying birds: the minimum power speed and the maximum range speed. The minimum power speed requires the lowest rate of energy expenditure per unit time to stay airborne and the maximum range speed maximizes air distance traveled per unit of energy consumed. Therefore, if birds aim to minimize the cost of transport under a range of wind conditions, they are predicted to fly at the maximum range speed. Furthermore, take-off is predicted to be strongly affected by wind speed and direction. To investigate the effect of wind conditions on take-off and cruising flight behavior, we equipped 14 European shags Phalacrocorax aristotelis with a back-mounted GPS logger to measure position and hence ground speed, and a neck-mounted accelerometer to record wing beat frequency and strength. Local wind conditions were recorded during the deployment period. Shags always took off into the wind regardless of their intended destination and take-off duration was correlated negatively with wind speed. We combined ground speed and direction during the cruising phase with wind speed and direction to estimate air speed and direction. Whilst ground speed was highly variable, air speed was comparatively stable, although it increased significantly during strong head winds, because of stronger wing beats. The increased air speeds in head winds suggest that birds fly at the maximum range speed, not at the minimum power speed. Our study demonstrates that European shags actively adjust their flight behavior to utilize wind power to minimize the costs of take-off and cruising flight.
  • Nobuo Kokubun, Takashi Yamamoto, Nobuhiko Sato, Yutaka Watanuki, Alexis Will, Alexander S. Kitaysky, Akinori Takahashi
    Biogeosciences Discussion 12 (21) 18151 - 18183 2016 [Refereed][Not invited]
  • Differential responses of seabirds to inter-annual environmental change in the continental shelf and oceanic habitats of southeastern Bering Sea
    Takashi Yamamoto, Nobuo Kokubun, Dale M. Kikuchi, Nobuhiko Sato, Akinori Takahashi, Alexis Will, Alexander S. Kitaysky, Yutaka Watanuki
    Biogeosciences Discussion 12 (21) 17693 - 17720 2016 [Refereed][Not invited]
  • Nobuo Kokubun, Takashi Yamamoto, Nobuhiko Sato, Yutaka Watanuki, Alexis Will, Alexander S. Kitaysky, Akinori Takahashi
    BIOGEOSCIENCES 13 (8) 2579 - 2591 1726-4170 2016 [Refereed][Not invited]
     
    Subarctic environmental changes are expected to affect the foraging ecology of marine top predators, but the response to such changes may vary among species if they use food resources differently. We examined the characteristics of foraging behavior of two sympatric congeneric diving seabird: common (Uria aalge: hereafter COMUs) and thick-billed (U. lomvia: hereafter TBMUs) murres breeding on St. George Island, located in the seasonal sea-ice region of the Bering Sea. We investigated their foraging trip and flight durations, diel patterns of dive depth, and underwater wing strokes, along with wing morphology and blood stable isotope signatures and stress hormones. Acceleration-temperature-depth loggers were attached to chick-guarding birds, and data were obtained from 7 COMUs and 12 TBMUs. Both species showed similar mean trip duration (13.2 h for COMUs and 10.5 h for TBMUs) and similar diurnal patterns of diving (frequent dives to various depths in the daytime and less frequent dives to shallow depths in the night-time). During the daytime, the dive depths of COMUs had two peaks in shallow (18.1 m) and deep (74.2 m) depths, while those of TBMUs were 20.2 m and 59.7 m. COMUs showed more frequent wing strokes during the bottom phase of dives (1.90 s(-1)) than TBMUs (1.66 s(-1)). Fish occurred more frequently in the bill loads of COMUs (85 %) than those of TBMUs (56 %). The delta N-15 value of blood was significantly higher in COMUs (14.5 parts per thousand) than in TBMUs (13.1 parts per thousand). The relatively small wing area (0.053 m(2)) of COMUs compared to TBMUs (0.067 m(2)) may facilitate their increased agility while foraging and allow them to capture more mobile prey such as larger fishes that inhabit deeper depths. These differences in food resource use may lead to the differential responses of the two murre species to marine environmental changes in the Bering Sea.
  • Takashi Yamamoto, Nobuo Kokubun, Dale M. Kikuchi, Nobuhiko Sato, Akinori Takahashi, Alexis P. Will, Alexander S. Kitaysky, Yutaka Watanuki
    BIOGEOSCIENCES 13 (8) 2405 - 2414 1726-4170 2016 [Refereed][Not invited]
     
    Seasonal sea-ice cover has been decreasing in the southeastern Bering Sea shelf, which might affect ecosystem dynamics and availability of food resources to marine top predators breeding in the region. In this study, we investigated the foraging responses of two seabird species, surface-foraging red-legged kittiwakes Rissa brevirostris (hereafter, RLKI) and pursuit-diving foraging thick-billed murres Uria lomvia (TBMU) to different marine environmental conditions over 2 years. At-sea distributions of RLKI and TBMU breeding on St. George Island, the largest seabird colony in the region, were recorded using GPS loggers, and blood samples were taken to examine their physiological condition and isotopic foraging niche in a given year. Between the study years, winter ice retreated earlier and summer water temperatures were relatively warmer in 2014 compared to those in 2013. RLKI foraging occurred mostly over the oceanic basin in both years. TBMU, however, foraged mostly over the shelf but showed a relatively higher use of the shelf break and oceanic basin in 2013. The foraging distances from the colony peaked at 250-300 km in 2013 and bimodally at 150-250 and 300-350 km in 2014 for RLKI and tended to be farther in 2013 compared to those in 2014 for TBMU. Plasma levels of corticosterone did not differ between the years in RLKI but differed in TBMU, showing higher levels of physiological stress incurred by murres in 2013, the year of relatively cooler sea surface temperatures with later sea-ice retreat. delta N-13 (a proxy of trophic level of prey) did not differ between the years in either RLKI or TBMU. These results suggest that the response of ecosystem dynamics to climate variability in the southeastern Bering Sea may differ between the ocean basin and continental shelf regions, which, in turn, may generate differential responses in seabirds relying on those habitats for foraging.
  • 綿貫 豊
    生態学会誌 66 109 - 117 2016 [Refereed][Not invited]
  • A red-footed booby catching airborne squid.
    Muramatsu K, Yamamoto J, Abe T, Nishizawa B, Hoshi N, Ohwada M, Watanuki Y, Sakurai Y
    J Yamashina Inst Ornithol 47 1 - 6 2016 [Refereed][Not invited]
  • Tomohiro Deguchi, Hiroko Nomura, Ryoko Otsuka, Masaru Wada, Yutaka Watanuki
    ORNITHOLOGICAL SCIENCE 15 (1) 15 - 21 1347-0558 2016/01 [Refereed][Not invited]
     
    Older or heavier Rhinoceros Auklet Cerorhinca monocerata chicks are less likely to remain in their nest during pre-fledging mass recession. Older or heavier chicks have longer wings but the individual variation in wing length at fledging is small. To identify proximate triggers of fledging from a mix of candidates when chicks experienced mass recession, we selected 30 nest boxes each containing a chick and provided half of them with 30-60 g of supplementary foods in an attempt to expand their variation in growth rate. When chicks reached the minimum wing length required for fledging (130 mm), we stopped all provisioning (supplementary and parental) by closing a hatch on the nest box entrance thereby simulating mass recession and inducing fledging. With these treatments, we examined whether timing of fledging (=duration of mass recession) was only triggered by wing length to a threshold size or whether timing of fledging was delayed by younger age at peak mass or lighter peak body mass. Our results indicate that younger chicks remained in their nests longer than older chicks at the beginning of pre-fledging mass recession, regardless of the small variation in wing length among individuals. Annual variation in the duration of mass recession was also detected but body mass was not the trigger for fledging. Measurement of baseline corticosterone level indicated a negative trend between the corticosterone level and the number of days between the measurement date and the fledging date.
  • Yamamoto Takashi, Watanuki Yutaka, Hazen Elliott L, Nishizawa Bungo, Sasaki Hiroko, Takahashi Akinori
    ECOLOGICAL APPLICATIONS 25 (8) 2394 - 2406 1051-0761 2015/12 [Refereed][Not invited]
  • Kosuke Tanaka, Hideshige Takada, Rei Yamashita, Kaoruko Mizukawa, Masa-aki Fukuwaka, Yutaka Watanuki
    ENVIRONMENTAL SCIENCE & TECHNOLOGY 49 (19) 11799 - 11807 0013-936X 2015/10 [Refereed][Not invited]
     
    Our previous study suggested the transfer of polybrominated diphenyl ether (PBDE) flame retardants from ingested plastics to seabirds' tissues. To understand how the PBDEs are transferred, we studied leaching from plastics into digestive fluids. We hypothesized that stomach oil, which is present in the digestive tract of birds in the order Procellariiformes, acts as an organic solvent, facilitating the leaching of hydrophobic chemicals. Pieces of plastic compounded with deca-BDE were soaked in several leaching solutions. Trace amounts were leached into distilled water, seawater, and acidic pepsin solution. In contrast, over 20 times as much material was leached into stomach oil, and over 50 times as much into fish oil (a major component of stomach oil). Analysis of abdominal adipose, liver tissue, and ingested plastics from 18 wild seabirds collected from the North Pacific Ocean showed the occurrence of deca-BDE or hexa-BDEs in both the tissues and the ingested plastics in three of the birds, suggesting transfer from the plastic to the tissues. In birds with BDE209 in their tissues, the dominance of BDE207 over other nona-BDE isomers suggested biological debromination at the meta position. Model calculation of PBDE exposure to birds based on the results of the leaching experiments combined with field observations suggested the dominance of plastic-mediated internal exposure to BDE209 over exposure via prey.
  • Alexis Will, Yutaka Watanuki, Dale M. Kikuchi, Nobuhiko Sato, Motohiro Ito, Matt Callahan, Katherine Wynne-Edwards, Scott Hatch, Kyle Elliott, Leslie Slater, Akinori Takahashi, Alexander Kitaysky
    ECOLOGY AND EVOLUTION 5 (19) 4221 - 4232 2045-7758 2015/10 [Refereed][Not invited]
     
    Changes in climate and anthropogenic pressures might affect the composition and abundance of forage fish in the world's oceans. The junk-food hypothesis posits that dietary shifts that affect the quality (e.g., energy content) of food available to marine predators may impact their physiological state and consequently affect their fitness. Previously, we experimentally validated that deposition of the adrenocortical hormone, corticosterone, in feathers is a sensitive measure of nutritional stress in seabirds. Here, we use this method to examine how changes in diet composition and prey quality affect the nutritional status of free-living rhinoceros auklets (Cerorhinca monocerata). Our study sites included the following: Teuri Is. Japan, Middleton Is. central Gulf of Alaska, and St. Lazaria Is. Southeast Alaska. In 2012 and 2013, we collected bill loads delivered by parents to feed their chicks (n=758) to document dietary changes. We deployed time-depth-temperature recorders on breeding adults (n=47) to evaluate whether changes in prey coincided with changes in foraging behavior. We measured concentrations of corticosterone in fledgling (n=71) and adult breeders' (n=82) feathers to determine how birds were affected by foraging conditions. We found that seasonal changes in diet composition occurred on each colony, adults dove deeper and engaged in longer foraging bouts when capturing larger prey and that chicks had higher concentrations of corticosterone in their feathers when adults brought back smaller and/or lower energy prey. Corticosterone levels in feathers of fledglings (grown during the breeding season) and those in feathers of adult breeders (grown during the postbreeding season) were positively correlated, indicating possible carryover effects. These results suggest that seabirds might experience increased levels of nutritional stress associated with moderate dietary changes and that physiological responses to changes in prey composition should be considered when evaluating the effect of prey quality on marine predators.
  • Nobuhiko N. Sato, Nobuo Kokubun, Takashi Yamamoto, Yutaka Watanuki, Alexander S. Kitaysky, Akinori Takahashi
    BIOLOGY LETTERS 11 (8) 1744-9561 2015/08 [Refereed][Not invited]
     
    High levels of jellyfish biomass have been reported in marine ecosystems around the world, but understanding of their ecological role remains in its infancy. Jellyfish are generally thought to have indirect negative impacts on higher trophic-level predators, through changes in lower trophic pathways. However, high densities of jellyfish in the water colunm may affect the foraging behaviour of marine predators more directly, and the effects may not always be negative. Here, we present novel observations of a diving seabird, the thick-billed murre, feeding on fish aggregating among the long tentacles of large jellyfish, by using small video loggers attached to the birds. We show that the birds encountered large jellyfish, Chrysaora melanaster, during most of their dives, commonly fed on fish associated with jellyfish, and appeared to specifically target jellyfish with a high number of fish aggregating in their tentacles, suggesting the use of jellyfish may provide significant energetic benefits to foraging murres. We conclude that jellyfish provide feeding opportunities for diving seabirds by concentrating forage fish, and that the impacts of jellyfish on marine ecosystems are more complex than previously anticipated and may be beneficial to seabirds.
  • Dale M. Kikuchi, Yutaka Watanuki, Nobuhiko Sato, Kenji Hoshina, Akinori Takahashi, Yuuki Y. Watanabe
    JOURNAL OF AVIAN BIOLOGY 46 (4) 406 - 411 0908-8857 2015/07 [Refereed][Not invited]
     
    Alcids propel themselves by flapping wings in air and water that have vastly different densities. We hypothesized that alcids change wing kinematics and maintain Strouhal numbers (St = fA/U, where f is wingbeat frequency, A is the wingbeat amplitude, and U is forward speed) within a certain range, to achieve efficient locomotion during both flying and swimming. We used acceleration and GPS loggers to measure the wingbeat frequency and forward speed of free-ranging rhinoceros auklets Cerorhinca monocerata during both flying and swimming. We also measured wingbeat amplitude from video footage taken in the wild. On average, wingbeat frequency, forward speed, and wingbeat amplitude were 8.9 Hz, 15.3 m s(-1), and 0.39 m, respectively, during flying, and 2.6 Hz, 1.3 m s(-1), and 0.18 m, respectively, during swimming. The smaller wingbeat amplitude during swimming was achieved by partially folding the wings, while maintaining the dorso-ventral wingbeat angle. Mean St was 0.23 during flying and 0.36 during swimming. The higher St value for swimming might be related to the higher thrust force required for propulsion in water. Our results suggest that rhinoceros auklets maintain St for both flying and swimming within the range (0.2-0.4) that propulsive efficiency is known to be high and St in both flying specialists and swimming specialists are known to converge.
  • Yutaka Watanuki, Takashi Yamamoto, Ai Yamashita, Chihiro Ishii, Yoshinori Ikenaka, Shouta M. M. Nakayama, Mayumi Ishizuka, Yuya Suzuki, Yasuaki Niizuma, C. E. Meathrel, R. A. Phillips
    JOURNAL OF ORNITHOLOGY 156 (3) 847 - 850 0021-8375 2015/07 [Refereed][Not invited]
     
    We measured mercury concentrations ([Hg]) and nitrogen stable isotope ratios (delta N-15) in the primary feathers of Short-tailed Shearwaters (Puffinus tenuirostris) that were tracked year-round. The [Hg] were highest in 14 birds that used the Okhotsk and northern Japan Seas during the non-breeding period (2.5 +/- A 1.4 mu g/g), lowest in nine birds that used the eastern Bering Sea (0.8 +/- A 0.2 mu g/g), and intermediate in five birds that used both regions (1.0 +/- A 0.5 mu g/g), with no effects of delta N-15. The results illustrate that samples from seabirds can provide a useful means of monitoring pollution at a large spatial scale.
  • Masayuki Senzaki, Makoto Hasebe, Yoshihiro Kataoka, Yoshihiro Fukuda, Bungo Nishizawa, Yutaka Watanuki
    WATERBIRDS 38 (2) 184 - 190 1524-4695 2015/06 [Refereed][Not invited]
     
    The Spectacled Guillemot (Cepphus carbo) is a seabird endemic to northeastern Asia. It is listed as a "Vulnerable" species in Japan, though little is known of its population status. Population surveys were carried out during 2011-2014 throughout their range in northern Japan. Twenty-eight known and six suspected breeding colonies were reported in this region during 1875-2010. Fourteen known and four suspected breeding colonies were found in the 2011-2014 surveys, with 1,169 individuals and 294 nests. Based on our analysis of the two survey periods, 19 colonies have apparently disappeared, and populations have decreased in 12 of the current colonies. Our models indicated that colonies with small numbers of individuals were most likely to disappear, whereas other environmental factors (i.e., colony type, latitude, and SST trends) had relatively minimal effects on local colony extirpation. Our study shows that the population status of the Spectacled Guillemot has deteriorated in Japan.
  • Akinori Takahashi, Motohiro Ito, Yuuya Suzuki, Yutaka Watanuki, Jean-Baptiste Thiebot, Takashi Yamamoto, Takahiro Iida, Phil Trathan, Yasuaki Niizuma, Tomohiro Kuwae
    MARINE ECOLOGY PROGRESS SERIES 525 229 - 243 0171-8630 2015/04 [Refereed][Not invited]
     
    Spatial and temporal variability in marine biological productivity may drive heterogeneity in seasonal resources available for marine animals in temperate waters. Migratory seabirds are expected to adjust their annual cycle of breeding activities and migratory movements to exploit seasonally available resources efficiently. We studied the movement and trophic position of rhinoceros auklets Cerorhinca monocerata breeding at Teuri Island, Japan Sea, during the nonbreeding and early breeding periods over 2 yr. After breeding, the auklets moved northward from the colony to the Sea of Okhotsk, where phytoplankton blooms enhanced biological productivity in autumn. The birds then moved southward to the southwestern Japan Sea (similar to 1470 km from the colony), where major epipelagic fish and squid concentrations have been reported in winter. Stable isotope analyses suggest that the auklets fed on higher-trophic level prey, including fish and/or squid during the autumn and winter nonbreeding periods. The auklets moved northward and returned to the colony in mid-March. During the early breeding period, the birds foraged close to the colony (similar to 380 km) on lower-trophic level prey including fish and/or krill, which were available during the spring phytoplankton bloom. The timing of the return migration does not match with the northward migration of warm-water anchovy, a profitable prey during summer, but may be related to timing the chick-rearing period to correspond with anchovy arrival. We suggest that rhinoceros auklets follow spatial and seasonal changes in prey availability by a distinctive '3-step' migration (first northward, second southward, third northward) in the temperate marine system of the northwestern Pacific.
  • Rebecca C. Young, Alexander S. Kitaysky, Chris P. Barger, Ine Dorresteijn, Motohiro Ito, Yutaka Watanuki
    ECOSPHERE 6 (3) 2150-8925 2015/03 [Refereed][Not invited]
     
    Telomeres are an increasingly studied component of physiological ecology. However, in long-lived birds a large telomere loss with chronological age is not the norm. Telomeres are now regarded less as a chronological aging tool and more as an indicator of individual quality, residual lifespan, or biological age. If telomeres indicate biological aging processes, then they should also be associated with other variables that change with age, especially foraging and reproductive behaviors. This study compared telomere length to a suite of foraging parameters in Thick-billed Murres breeding on three colonies in the Bering Sea. Telomere length, environmental conditions at colonies, and sex played pivotal roles in determining foraging habitat selection. Spatial habitat use, foraging efficiency, and prey selection variables all changed with telomere length. The behavioral evidence indicates that despite losing telomeres, birds with short telomere length retain their ability to use the environment efficiently. This indicates that aging birds remain behaviorally flexible, despite paying physiological costs. Changes in spatial use were largely sex-dependent: females and males differed in their use of the environment as telomere lengths declined. Prey selection was related to telomere length and colony; changes in murre trophic level depended on telomere length, but their direction also depended on habitat quality. We found much support for the continued able functioning of birds with shorter telomeres, indicating that physiological aging does not carry only costs. Murres appear to modify their behavior depending on environmental conditions as their physiological reserves decline.
  • Takashi Yamamoto, Kenji Hoshina, Bungo Nishizawa, Catherine E. Meathrel, Richard A. Phillips, Yutaka Watanuki
    MARINE BIOLOGY 162 (2) 413 - 424 0025-3162 2015/02 [Refereed][Not invited]
     
    The marine ecosystems of the Bering Sea and adjacent southern Chukchi Sea are experiencing rapid changes due to recent reductions in sea ice. Short-tailed shearwaters Puffinus tenuirostris visit this region in huge numbers between the boreal summer and autumn during non-breeding season, and represent one of the dominant top predators. To understand the implications for this species of ongoing environmental change in the Pacific sub-Arctic and Arctic seas, we tracked the migratory movements of 19 and 24 birds in 2010 and 2011, respectively, using light-level geolocators. In both years, tracked birds occupied the western (Okhotsk Sea and Kuril Islands) and eastern (southeast Bering Sea) North Pacific from May to July. In August-September of 2010, but not 2011, a substantial proportion (68 % of the tracked individuals in 2010 compared to 38 % in 2011) moved through the Bering Strait to feed in the Chukchi Sea. Based on the correlation with oceanographic variables, the probability of shearwater occurrence was highest in waters with sea surface temperatures (SSTs) of 8-10 A degrees C over shallow depths. Furthermore, shearwaters spent more time flying when SST was warmer than 9 A degrees C, suggesting increased search effort for prey. We hypothesized that the northward shift in the distribution of shearwaters may have been related to temperature-driven changes in the abundance of their dominant prey, krill (Euphausiacea), as the timing of krill spawning coincides with the seasonal increase in water temperature. Our results indicate a flexible response of foraging birds to ongoing changes in the sub-Arctic and Arctic ecosystems.
  • 長谷部真, 福田佳弘, 先崎理之, 綿貫豊
    64 251 - 255 2015 [Refereed][Not invited]
  • Yamamoto T, Watanuki Y, Hazen EL, Nishizawa B, Ssasaki H, Takahashi A
    Ecological Applications 25 2394 - 2406 2015 [Refereed][Not invited]
  • 粂佑奈, 新妻靖章, 風間健太郎, 伊藤元裕, 山下麗, 綿貫豊
    日本鳥学会誌 64 219 - 226 2015 [Refereed][Not invited]
  • Chihiro Ishii, Yoshinori Ikenaka, Shouta M. M. Nakayama, Yuya Suzuki, Yutaka Watanuki, Yuji Watanabe, Yared Beyene Yohannes, Hazuki Mizukawa, Mayumi Ishizuka
    JAPANESE JOURNAL OF VETERINARY RESEARCH 62 (3) 143 - 149 0047-1917 2014/08 [Refereed][Not invited]
     
    Teuri Island, Hokkaido in Japan is an important place for seabirds breeding. We measured the concentrations of heavy metals (Hg, Cd, Cr, Co, Ni, Cu, Zn, and Pb) and a metalloid (As) in rhinoceros auklet (Cerorhinca monocerata) (n = 7), thick-billed murre (Uria lomvia) (n = 2), spectacled guillemot (Cepphus carbo) (n = 6), slaty-backed gull (Larus schistisagus) (n = 15), jungle crow (Corvus macrorhynchos) (n = 3), Japanese anchovy (Engraulis japonica) (n = 6) and Atka mackerel (Pleurogrammus azonus) (n = 2). Spectacled guillemot had high As concentrations, with its source being their feeding habitat. Concentration of Hg in kidney of jungle crow was higher than other seabird species at Teuri.
  • Alexis P. Will, Yuya Suzuki, Kyle H. Elliott, Scott A. Hatch, Yutaka Watanuki, Alexander S. Kitaysky
    JOURNAL OF EXPERIMENTAL BIOLOGY 217 (13) 2371 - 2376 0022-0949 2014/07 [Refereed][Not invited]
     
    In nest-bound avian offspring, food shortages typically trigger a release of the stress hormone corticosterone (CORT). Recent studies indicate that CORT is passively deposited in the tissue of growing feathers and thus may provide an integrated measure of stress incurred during development in the nest. The current hypothesis predicts that, assuming a constant rate of feather growth, elevated CORT circulating in the blood corresponds to higher levels of CORT in feather tissue, but experimental evidence for nutritionally stressed chicks is lacking. Here, we examined how food limitation affects feather CORT content in the rhinoceros auklet (Cerorhinca moncerata). We (i) used captive chicks reared on control versus restricted diets, and (ii) applied this technique to free-living chicks with unknown nutritional histories that fledged at three separate colonies. We found that (i) feather growth was not affected by experimentally induced nutritional stress; (ii) captive chicks raised on a restricted diet had higher levels of CORT in their primary feathers; (iii) feather CORT deposition is a sensitive method of detecting nutritional stress; and (iv) free-living fledglings from the colony with poor reproductive performance had higher CORT in their primary feathers. We conclude that feather CORT is a sensitive integrated measure revealing the temporal dynamics of food limitations experienced by rhinoceros auklet nestlings. The use of feather CORT may be a powerful endocrine tool in ecological and evolutionary studies of bird species with similar preferential allocation of limited resources to feather development.
  • Masayuki Senzaki, Yuya Suzuki, Yutaka Watanuki
    ORNITHOLOGICAL SCIENCE 13 (1) 1 - 8 1347-0558 2014/06 [Refereed][Not invited]
     
    Diurnal gulls and skuas, which depend mostly on visual cues during kleptoparasitic attacks, experience reduced predation success when low light conditions or dense vegetation impair prey visibility. Rhinoceros Anklets Cerorhinca monocerata lose prey to kleptoparasitic conspecifics and kleptoparasitic gulls. The return of adult anklets to their colony was observed and incidences of inter- and intra-specific kleptoparasitism were recorded in five study sites with high and low vegetation coverage under variable conditions of illumination, Whereas gulls (Black-tailed Larus crassirostris and Slaty-backed L. schistisagus) mainly attacked anklets in flight in the early evening and from distances exceeding five metres, anklets attacked later in the evening after anklet numbers on the ground had increased, and only when closer than two metres. Intra-specific kleptoparasitism occurred less frequently in sites with dense vegetation and where the visible range was short. These findings indicate that environmental factors facilitating kleptoparasitism among gulls (aerial pirates) and anklets (close-quarter terrestrial pirates) are different.
  • Cathryn L. Abbott, Rhonda L. Millikin, Mark J. Hipfner, Scott Hatch, Motohiro Ito, Yutaka Watanuki, Theresa M. Burg
    MARINE BIOLOGY 161 (2) 275 - 283 0025-3162 2014/02 [Refereed][Not invited]
     
    Data from eight microsatellite markers screened in 246 rhinoceros auklets (Cerorhinca monocerata) from across the North Pacific revealed multiple genetic groups. The east (North America) to west (Japan) split was clearly evident in all analyses. Within the eastern Pacific, a minimum of three genetic groups are present. Surprisingly, rhinoceros auklets from Triangle Island, British Columbia, were genetically isolated from other nearby populations, including the breeding colony on Pine Island (similar to 100 km to the east). A fourth genetic cluster (Chowiet Is) was detected using principal coordinate's analysis; however, sample sizes were limited. Patterns of differentiation correspond to nonbreeding distributions with the eastern and western Pacific birds spending time off the west coast of North America and Japan, respectively, and may represent historical isolation in separate refugia during the Pleistocene glaciations. The patterns of genetic structure result from a combination of historical and contemporary factors influencing dispersal of rhinoceros auklets.
  • Maria I. Bogdanova, Sarah Wanless, Michael P. Harris, Jan Lindstroem, Adam Butler, Mark A. Newell, Katsufumi Sato, Yutaka Watanuki, Matt Parsons, Francis Daunt
    BIOLOGICAL CONSERVATION 170 292 - 299 0006-3207 2014/02 [Refereed][Not invited]
     
    Marine spatial planning aims to deliver sustainable use of marine resources by minimizing environmental impacts of human activities and designating Marine Protected Areas. This poses a challenge where species' distributions show spatio-temporal heterogeneity. However, due to logistic constraints and challenging timescales many studies of distribution are undertaken over few years or on a restricted subset of the population. Long-term studies can help identify the degree of uncertainty in those less comprehensive in space and time. We quantify inter-annual and sub-colony variation in the summer foraging distribution of a population of European shags Phalacrocorax aristotelis, using a tracking data set comprising 320 individuals and 1106 foraging trips in 15 years from 1987 to 2010. Foraging distribution over the study period was concentrated in three areas. Data from one and two years captured an average of 54% and 64% of this distribution, respectively, but it required 8 years' data to capture over 90% of the distribution. Foraging range increased with population size when breeding success was low, suggesting interplay between extrinsic and intrinsic effects. Furthermore, females had foraging ranges on average 36% greater than males. Finally, sub-colony segregation occurred in foraging areas up to 4 km from the colony and in the most distant locations (>10 km), whilst there was considerable overlap at intermediate distances (6-10 km). Our study highlights important considerations for marine spatial planning in particular, and species conservation in general, notably the proportion of the population distribution identified, the prevailing conditions experienced and the need for balanced sampling across the population. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).
  • Habitat of two albatross species during non-breeding season in the North Pacific Transition Zone.
    Nishizawa B, Ochi D, Minami H, Tokawa K, Saito S, Watanuki Y
    Mar Biol In Press DOI 10.1007/s00227-015-2620-1 2014 [Refereed][Not invited]
  • 鈴木優也, 伊藤元裕, 風間健太郎, 新妻靖章, 綿貫豊
    日本鳥学会誌 63 279 - 287 2014 [Refereed][Not invited]
  • Chris B. Thaxter, Francis Daunt, David Gremillet, Mike P. Harris, Silvano Benvenuti, Yutaka Watanuki, Keith C. Hamer, Sarah Wanless
    PLOS ONE 8 (11) e79915  1932-6203 2013/11 [Refereed][Not invited]
     
    Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bioenergetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5 +/- 0.8 items per dive (0.8 +/- 0.4 and 1.1 +/- 0.6 items per minute foraging and underwater, respectively) for guillemots and 3.7 +/- 2.4 items per dive (4.9 +/- 3.1 and 7.3 +/- 4.0 items per minute foraging and underwater, respectively) for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus) length (prediction 1), but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2), and lower in prey density (prediction 3). Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6), thus not supporting prediction 3. This bio-energetics approach complements other foraging models in predicting likely impacts of environmental change on marine higher predators dependent on species-specific foraging ecologies.
  • Kentaro Kazama, Kazuhiko Hirata, Takashi Yamamoto, Hiroshi Hashimoto, Akinori Takahashi, Yasuaki Niizuma, Philip N. Trathan, Yutaka Watanuki
    JOURNAL OF AVIAN BIOLOGY 44 (6) 603 - 608 0908-8857 2013/11 [Refereed][Not invited]
     
    Long-lived animals sometimes skip one or more breeding seasons; however, little is known about their movements and activities during such sabbatical' periods. Here we present novel data on year-round movements and activities of two male black-tailed gulls Larus crassirostris during a sabbatical year. We compare the data with those in a year when they bred and with those of two other breeding males. The year-round migration routes of two sabbatical males were consistent with those of the breeding males: they returned to the breeding area but did not visit the colony in the sabbatical year. They landed more frequently on water (a potential index of foraging effort) during the non-breeding autumn and winter prior to the sabbatical year than before breeding. Sabbatical gulls may forage more intensively to recover body condition immediately after breeding.
  • Kosuke Tanaka, Hideshige Takada, Rei Yamashita, Kaoruko Mizukawa, Masa-aki Fukuwaka, Yutaka Watanuki
    MARINE POLLUTION BULLETIN 69 (1-2) 219 - 222 0025-326X 2013/04 [Refereed][Not invited]
     
    We analyzed polybrominated diphenyl ethers (PBDEs) in abdominal adipose of oceanic seabirds (short-tailed shearwaters, Puffinus tenuirostris) collected in northern North Pacific Ocean. In 3 of 12 birds, we detected higher-brominated congeners (viz., BDE209 and BDE183), which are not present in the natural prey (pelagic fish) of the birds. The same compounds were present in plastic found in the stomachs of the 3 birds. These data suggested the transfer of plastic-derived chemicals from ingested plastics to the tissues of marine-based organisms. (C) 2012 Elsevier Ltd. All rights reserved.
  • Heavy metal pollution in Japanese seabirds.
    Chihiro Ishii, Yoshinori Ikenaka, Shouta M M Nakayama, Yuya Suzuki, Yutaka Watanuki, Yuji Watanabe, Masa-aki Fukuwaka, Yared B Yohannes, Yusuke K Kawai, Mayumi Ishizuka
    The Japanese journal of veterinary research 61 Suppl S75-6 - 6 0047-1917 2013/02 [Refereed][Not invited]
     
    It is reported that seabirds accumulate high levels of metals, prompting concerns regarding poisoning. The present study investigated the accumulation patterns of metals in tissues among four species of seabirds (Fratercula corniculata, Uria lomvia, Puffinus tenuirostris, and Fulmarus glacialis). Furthermore, we focused on Slaty-backed Gulls, which accumulated high levels of cadmium and mercury, and compared the areal differences. Geographic variation of metal levels could also contribute to differences in metal accumulation levels in these bird species. Therefore, the concentrations of metals in seabirds are considered to reflect their habitat. There are differences in the accumulation pattern among the seabird species. The high accumulation of metals could affect seabirds even if they do not show any symptoms.
  • Ito A, Yamashita R, Takada H, Yamamoto T, Shiomi K, Zavalaga C, Abe T, Watanabe S, Yamamoto M, Sato K, Kohno H, Iida T, Yoda K, Watanuki Y
    Environ Sci Technol 47 7862 - 7867 2013 [Refereed][Not invited]
  • Kentaro Kazama, Yasuaki Niizuma, Yutaka Watanuki
    WATERBIRDS 35 (4) 599 - 607 1524-4695 2012/12 [Refereed][Not invited]
     
    To understand the adaptive significance of colonial breeding, evaluating the costs and benefits that colonial breeding provides to individuals is necessary. To study some of these costs and benefits of colonial breeding, over 24,000 nest-hour observations of kleptoparasitism (stealing of food being fed to young), intraspecific attacks on and killing of chicks; and chick adoption were conducted in colonial breeding Black-tailed Gulls (Larus crassirostris) during two breeding seasons. Although kleptoparasitism was rarely observed (under 0.001 events/nest/observational hour), the occurrence of chick-attacks was 5-10 times higher (0.005-0.01 events/nest/observational hour) than that of kleptoparasitism, with over 10% of the attacks resulting in the death or disappearance of chicks. More than 60% of all attacks on chicks were by failed breeders and non-breeding adult floaters. The survival of attacked chicks reached 98-100% if they escaped into other nests and were accepted by "foster" adults, or if they were defended by non-parental,adults. Chick adoption and non-parental defense were more likely to be observed among breeding neighbors (52-60% of chick adoptions and almost all examples of non-parental defense) than among non-neighbors. An increased chick survival rate, resulting from nesting in close to proximity to conspecific neighbors, was considered as a factor promoting colonial breeding among the Laridae. Received 20 January 2012, accepted 5 August 2012.
  • Motohiro Ito, Kentaro Kazama, Yasuaki Niizuma, Hiroshi Minami, Yuzan Tanaka, Yutaka Watanuki
    ORNITHOLOGICAL SCIENCE 11 (2) 113 - 119 1347-0558 2012/12 [Refereed][Not invited]
     
    Carbon and nitrogen stable-isotope ratios were measured in the egg yolks of four species of seabirds in Teuri Island and Rishiri Island, Japan. Delta N-15 of the yolks of Rhinoceros Auklets Cerorhinca monocerata (11.2-12.3 parts per thousand) and Black-tailed Gulls Larus crassirostris (11.3-12.5 parts per thousand) were lower than those of Slaty-backed Gulls Larus schistisagus (13.4-14.2%0) and Japanese Cormorants Phalacrocorax capillatus (14.0-16.2 parts per thousand); suggesting that the former two species foraged mainly on low trophic level small fishes and sometimes on krill, while the latter two species fed on higher trophic level prey and larger fishes.
  • Kei Matsumoto, Nariko Oka, Daisuke Ochi, Fumihito Muto, Takashi P. Satoh, Yutaka Watanuki
    ORNITHOLOGICAL SCIENCE 11 (1) 9 - 19 1347-0558 2012/06 [Refereed][Not invited]
     
    Foraging behavior and diet of Streaked Shearwaters Calonectris leucomelas rearing chicks on Mikura Island was studied using depth and temperature recording data-loggers and stomach contents. Water mass where birds were foraging was estimated using sea surface temperature experienced by birds. Birds spent 76-96% of their time at sea flying, 4-24% for landing on the water, and made a few (0.5-17.0 per day) shallow (<6 m) dives. Birds made many short (<2 days) and some long (4-10 days) trips. During short trips, birds stayed in the warmer Kuroshio and Kuroshio-Oyashio mixed regions, and fed on Japanese Anchovy Engraulis japonicus, Common Squid Todarodes pacificus and Flying Fish Cypselurus hiraii. During long trips, birds stayed in the colder Oyashio region and fed on anchovy and Pacific Saury Cololabis saira. Birds made more dives during short trips than they did during long trips. Streaked Shearwaters breeding on the island in low productive Kuroshio water, therefore, adopted dual foraging strategies, and changed their diet and dive frequencies in relation to water masses.
  • Makoto Hasebe, Matsutoshi Aotsuka, Takaki Terasawa, Yoshihiro Fukuda, Yasushi Niimura, Yuji Watanabe, Yutaka Watanuki, Haruo Ogi
    ORNITHOLOGICAL SCIENCE 11 (1) 29 - 38 1347-0558 2012/06 [Refereed][Not invited]
     
    The Common Murre Uria aalge is listed as an endangered species in Japan and breeds only on Teuri Island, Hokkaido. The Teuri Island population has decreased from 8,000 birds in 1963 to 19 in 2010. They bred on sea-stack and cliff ledges (open habitat) before 1994, but mostly in cliff caves (closed habitat) after 1994. In closed habitat, the fledging rate was greater and the rate of population decrease was smaller than in open habitat. Restoration actions (decoys and sounds) were effective in attracting murres, but did not enhance the fledging rate sufficiently to raise their population, possibly because of predation by avian predators (Slaty-backed Gulls Lams schistisagus and Jungle Crows Corvus macrorhynchos). Using the fledging rate observed in closed habitat and other demographic parameters found in references, Population Viability Analysis shows that the probability of extinction of the Teuri population within 50 years is 66%. To improve the fledging rate and make the restoration actions more effective, we recommend the control of avian predators.
  • Kentaro Kazama, Yasuaki Niizuma, Yutaka Watanuki
    JOURNAL OF ETHOLOGY 30 (2) 279 - 288 0289-0771 2012/05 [Refereed][Not invited]
     
    Individual behaviors of animals do not evolve separately; they do so in association with other behaviors caused by single shared genetic or physiological constraints and/or favored by selection. Thus, measuring behavioral syndromes-suites of correlated behaviors across different contexts-leads to a better understanding of the adaptive significance of variations in behaviors. However, relatively few studies have examined behavioral syndromes in wild animal populations in changing environments. We investigated a potential behavioral syndrome across antipredator nest defense, territorial defense, chick provisioning, and mating behaviors of male Black-tailed Gulls Larus crassirostris in two successive years under different conspecific territorial intrusion risks and food conditions. Males that presented high levels of antipredator nest defense (aggressive antipredator defenders) against a crow decoy (crows are egg predators) defended their territories against conspecific intruders more frequently than did other males (nonaggressive antipredator defenders), independent of the risk of intrusion. Aggressive antipredator defenders also fed their chicks more frequently than nonaggressive males, but only in a year of low food availability. Taken together, this indicates that males show consistent aggressiveness regardless of breeding context (antipredator and territorial defense), but can regulate food provisioning according to food availability.
  • Fumi Hirose, Kentaro Kazama, Motohiro Ito, Yutaka Watanuki
    IBIS 154 (2) 296 - 306 0019-1019 2012/04 [Refereed][Not invited]
     
    In some bird species, the survival of chicks hatching later in the season is lower than those hatched earlier due to increased risk of predation and a seasonal decline in feeding conditions. To reduce these risks, it might be advantageous for late-hatched chicks to grow faster and hence fledge at younger age. In this experimental study, the growth rates of early- and late-hatched Rhinoceros Auklet Cerorhinca monocerata chicks were compared under average and poor food supplies in captivity. Controlling for potentially confounding effects of chick mass at 10 days old, chick age and nest-chamber temperature, late-hatched chicks had higher wing growth rate than early-hatched chicks before attaining the minimum wing length required for fledgling under both average and poor food supplies. After attaining the minimum wing length, however, late-hatched chicks had a lower fledging mass, indicating a potential cost that could diminish the early advantage of fast wing growth.
  • Takahashi K, Takahashi M, Misumi H, Deguchi T, Watanuki Y
    Entomol. Zool 63 231 - 234 2012 [Refereed][Not invited]
  • Lewison R, Oro D, Godley BJ, Underhill L, Bearhop S, Wilson RP, Ainley D, Acros JM, Boersma PD, Borboroglu PG, Boulinier T, Frederiksen M, Genovart M, Gonzalez-Solis J, Green JA, Gremillet D, Hamer KC, Hilton GM, Hyrenbach KD, Martinez-Abrain A, Montevecchi WA, Phillips RA, Ryan PG, Sagar P, Sydeman WJ, Wanless S, Watanuki Y, Weimerskirch H, Yorio P
    Endangered Species Research 17 93 - 121 2012 [Refereed][Invited]
  • Takahashi K, Takahashi M, Misumi H, Deguchi T, Watanuki Y
    Med. Entomol. Zool 63 231 - 234 2012 [Refereed][Not invited]
  • Lewison R, Oro D, Godley BJ, Underhill L, Bearhop S, Wilson RP, Ainley D, Acros JM, Boersma PD, Borboroglu PG, Boulinier T, Frederiksen M, Genovart M, Gonzalez-Solis J, Green JA, Gremillet D, Hamer KC, Hilton GM, Hyrenbach KD, Martinez-Abrain A, Montevecchi WA, Phillips RA, Ryan PG, Sagar P, Sydeman WJ, Wanless S, Watanuki Y, Weimerskirch H, Yorio P
    Endangered Species Research 17 93 - 121 2012 [Refereed][Invited]
  • 井上裕紀子, 藤井英紀, 黒木博文, 土屋健児, 新妻靖章, 綿貫豊
    日本鳥学会誌 61 6 - 16 2012 [Refereed][Not invited]
  • Yutaka Watanuki, Motohiro Ito
    MARINE ECOLOGY PROGRESS SERIES 454 183 - 196 0171-8630 2012 [Refereed][Invited]
     
    Seabirds as marine top predators have been put forth as reliable indicators of ecosystem change. To understand climate-ecosystem change in the northern Japan Sea, we studied the timing of breeding, chick diets, and breeding success of 3 seabird species almost continuously over 26 yr on Teuri Island, 1984 through 2009. Key climate drivers in this region are: (1) westerly winter winds that cool the atmosphere and the ocean and (2) the northward flowing Tsushima Current (TC) that warms the ocean in late spring and summer. Chick diet showed decadal changes in coastal pelagic fish, with a switch from sardine Sardinops melanostictus to anchovy Engraulis japonicus in the late 1980s corresponding to intensification of the TC. There were no long-term trends in the timing of breeding or breeding success of rhinoceros auklet Cerorhinca monocerata and Japanese cormorant Phalacrocorax filamentosus, but these variables were affected by interannual variation in spring air and sea temperatures, as well as the timing of TC warm water intrusions within the foraging range (similar to 60 km from the colony) of the birds. Effects include: (1) freezing of the breeding grounds by winter winds limiting access to nesting grounds and (2) availability of anchovy and sandlance Ammodytes personatus affecting chick diet, growth, and breeding success. We did not detect relationships between chlorophyll a concentrations and the availability of prey species. The timing and success of black-tailed gulls Larus crassirostris, which fed mainly on sandlance, however, could not be explained by these factors. Our study indicates potential links between the Pacific Decadal Oscillation index and the flow rate of the TC, and between the Arctic Oscillation index and local wind stress, and suggests that broad-scale atmospheric pressure fields influence local weather, oceanography, and seabirds indirectly through changes in prey availability.
  • Matsumoto K, Oka N, Ochi D, Muto F, Satoh TP, Watanuki Y
    Ornith Sci 11 9 - 19 2012 [Refereed][Not invited]
  • 倉沢康大, 板橋豊, 山本麻希, 綿貫豊
    日本鳥学会誌 61 137 - 141 2012 [Refereed][Not invited]
  • Rei Yamashita, Hideshige Takada, Masa-aki Fukuwaka, Yutaka Watanuki
    MARINE POLLUTION BULLETIN 62 (12) 2845 - 2849 0025-326X 2011/12 [Refereed][Not invited]
     
    We investigated the plastics ingested by short-tailed shearwaters, Puffinus tenuirostris, that were accidentally caught during experimental fishing in the North Pacific Ocean in 2003 and 2005. The mean mass of plastics found in the stomach was 0.23 g per bird (n = 99). Plastic mass did not correlate with body weight. Total PCB (sum of 24 congeners) concentrations in the abdominal adipose tissue of 12 birds ranged from 45 to 529 ng/g-lipid. Although total PCBs or higher-chlorinated congeners, the mass of ingested plastic correlated positively with concentrations of lower-chlorinated congeners. The effects of toxic chemicals present in plastic debris on bird physiology should be investigated. (C) 2011 Elsevier Ltd. All rights reserved.
  • Kentaro Kazama, Yasuaki Niizuma, Kentaro Q. Sakamoto, Yutaka Watanuki
    CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE 89 (10) 938 - 944 0008-4301 2011/10 [Refereed][Not invited]
     
    The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls (Larus crassirostris Vieillot, 1818) over 2 years. Only 30%-40% of males attacked a decoy of an egg predator (Large-billed Crow (Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male's, but not female's, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.
  • Kanako Toge, Rei Yamashita, Kentaro Kazama, Masaaki Fukuwaka, Orio Yamamura, Yutaka Watanuki
    PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 278 (1718) 2584 - 2590 0962-8452 2011/09 [Refereed][Not invited]
     
    Seabirds and large fishes are important top predators in marine ecosystems, but few studies have explored the potential for competition between these groups. This study investigates the relationship between an observed biennial change of pink salmon (Oncorhynchus gorbuscha) biomass in the central Bering Sea (23 times greater in odd-numbered than in even-numbered years) and the body condition and diet of the short-tailed shearwater (Puffinus tenuirostris) that spends the post-breeding season there. Samples were collected with research gill nets over seven summers. Both species feed on krill, small fishes and squid. Although the mean pink salmon catch per unit effort (in mass) over the study region was not related significantly with shearwater's stomach content mass or prey composition, the pink salmon biomass showed a negative and significant relationship with the shearwater's body mass and liver mass (proxies of energy reserve). We interpret these results as evidence that fishes can negatively affect mean prey intake of seabirds if they feed on a shared prey in the pelagic ecosystem.
  • Kentaro Kazama, Kentaro Q. Sakamoto, Yasuaki Niizuma, Yutaka Watanuki
    ORNITHOLOGICAL SCIENCE 10 (1) 13 - 19 1347-0558 2011/06 [Refereed][Not invited]
     
    Testosterone affects male sexual-, aggressive-, and parental-behaviors in bird species. To understand the breadth of the proximate contribution of testosterone to breeding behaviors in male Black-tailed Gulls Larus crassirostris, sexual behaviors, aggressive behaviors against egg-predators and conspecifics, and chick-provisioning behavior of five testosterone-implanted males (T-males) were observed and compared with those of three control males (placebo-implanted; C-males). T-males showed significantly higher levels of courtship and copulation behaviors than C-males. The levels of aggressiveness against egg-predators and against conspecifics, and the rate of feeding of chicks did not differ between T- and C-males. These results suggest that sexual and mating behaviors in male Black-tailed Gulls may be affected by testosterone, while aggressive- and feeding-behaviors are affected by certain ecological factors, such as individual age, or a necessity for high levels of feeding by males, rather than by testosterone.
  • Maki Yamamoto, Akiko Kato, Yasuaki Niizuma, Yutaka Watanuki, Yasuhiko Naito
    ORNITHOLOGICAL SCIENCE 10 (1) 27 - 34 1347-0558 2011/06 [Refereed][Not invited]
     
    Alcids dive longer than are predicted by their body size alone, but the physiological mechanisms that explain their excellent diving capabilities are poorly understood. In this study, we estimated the oxygen stores of Rhinoceros Auklets Cerorhinca monocerata, medium-sized alcids that attained depths down to 62 m within 2.5 min. Hematocrit was 43.9+/-2.8%, hemoglobin concentration was 17.2+/-4.6 g.100 ml(-1), and blood volume was 12.7+/-1.9% of their body mass. Myoglobin concentration in breast muscle (1.8+/-0.3 g.100 g(-1)) was higher than that in leg muscle (1.2+/-0.2 g.100 g(-1)). Rhinoceros Auklets have higher blood volume, hemoglobin and myoglobin concentrations, as do other flying/diving seabirds (other alcids and cormorants), than flying/non-diving seabirds (terns and kittiwakes). The oxygen store of Rhinoceros Auklets was estimated at 54.5 ml.kg(-1). Using the average oxygen consumption rate of diving seabirds (1.01 ml.s(-1).kg(-1)) we calculated their theoretical aerobic dive limit (TADL) as 53.9 s. Nearly half of their dives (47.2%) exceeded their TADL, because an overestimation of their oxygen consumption rate during diving resulted in an underestimation of TADL.
  • Yuuki Y. Watanabe, Katsufumi Sato, Yutaka Watanuki, Akinori Takahashi, Yoko Mitani, Masao Amano, Kagari Aoki, Tomoko Narazaki, Takashi Iwata, Shingo Minamikawa, Nobuyuki Miyazaki
    JOURNAL OF ANIMAL ECOLOGY 80 (1) 57 - 68 0021-8790 2011/01 [Refereed][Not invited]
     
    P>1. Breath-hold divers are widely assumed to descend and ascend at the speed that minimizes energy expenditure per distance travelled (the cost of transport (COT)) to maximize foraging duration at depth. However, measuring COT with captive animals is difficult, and empirical support for this hypothesis is sparse. 2. We examined the scaling relationship of swim speed in free-ranging diving birds, mammals and turtles (37 species; mass range, 0 center dot 5-90 000 kg) with phylogenetically informed statistical methods and derived the theoretical prediction for the allometric exponent under the COT hypothesis by constructing a biomechanical model. 3. Swim speed significantly increased with mass, despite considerable variations around the scaling line. The allometric exponent (0 center dot 09) was statistically consistent with the theoretical prediction (0 center dot 05) of the COT hypothesis. 4. Our finding suggests a previously unrecognized advantage of size in divers: larger animals swim faster and thus could travel longer distance, search larger volume of water for prey and exploit a greater range of depths during a given dive duration. 5. Furthermore, as predicted from the model, endotherms (birds and mammals) swam faster than ectotherms (turtles) for their size, suggesting that metabolic power production limits swim speed. Among endotherms, birds swam faster than mammals, which cannot be explained by the model. Reynolds numbers of small birds (< 2 kg) were close to the lower limit of turbulent flow (similar to 3 x 105), and they swam fast possibly to avoid the increased drag associated with flow transition.
  • 倉沢康大, 本田聡, 綿貫豊
    日本鳥学会誌 60 216 - 227 2011 [Refereed][Not invited]
  • 気候変化と海鳥の繁殖タイミングおよび生産
    綿貫豊
    北大水産紀要 53 19 - 26 2011 [Not refereed][Not invited]
  • Kentaro Kazama, Yutaka Watanuki
    BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY 64 (8) 1239 - 1246 0340-5443 2010/08 [Refereed][Not invited]
     
    Often in colonial seabirds, all colony members are believed to defend against nest predators and experience equal nest predation risk. However, the variation of defense behavior among members and its reproductive consequences are largely unknown. We investigated (1) individual variation in the nest defense of breeding Black-tailed Gulls Larus crassirostris against a natural egg predator, the Jungle Crow Corvus macrorhynchos and (2) how this behavioral variation affects an individual's own nest predation risk and that of their neighbors. Results were compared between 2 years where crow attack levels were manipulated to average 5 and 22 times normal rates ("low" and "high" predation risk years, respectively) by the placement of varying numbers of artificial nests containing unguarded eggs at the perimeter of the gull colony. In both years, 23-38% of parents, mostly males, showed "aggressive" defense behavior (strikes or chases) against crows and decoys. Other "non-aggressive" gulls showed no defense. In the year of low predation risk, intrusion rates by crows (landing within 0.5 m of an individual gull's nest) were similar for aggressive and non-aggressive gulls. In the year of high predation risk, however, the rates of intrusion for aggressive gulls (4%) and for non-aggressive gulls with an aggressive neighbor (37%) were significantly lower than for non-aggressive gulls without an aggressive neighbor (76%). These results indicate that aggressive individuals reduce nest predation risk for themselves and conspecific neighbors in a colonially breeding species.
  • Yutaka Watanuki, Akinori Takahashi, Katsufumi Sato
    AUK 127 (3) 523 - 531 0004-8038 2010/07 [Refereed][Not invited]
     
    To understand the effects of foraging behavior on the amount of food provided to chicks (meal mass and frequency), we monitored nest attendance and diving behavior of 20 Adelie Penguin (Pygoscelis adeliae) pairs that were rearing chicks. Because ice forms on the sea surface at night, parents foraged through cracks or within leads in the sea ice mainly during 0800-2400 hours. Birds that departed the colony in the afternoon and returned in the evening of the same day fed their chicks more frequently than those that made longer trips (i.e., those that departed in the afternoon and returned the next day or departed in the early morning and returned that evening). When the duration of the longest dive bout during each trip was longer, parents brought back heavier meals that contained larger krill. On average, birds made longer dive bouts when diving to greater depths. Thus, daily foraging pattern and foraging depth affected the provisioning rate, but the proportion of time spent foraging during the potential foraging period, total underwater time per day, and parental body condition were not. We suggest that temporal variability in prey availability and individual differences in foraging behavior affect the provisioning rate and, thus, chick growth. Received 1 August 2008, accepted 4 November 2009.
  • Kentaro Kazama, Yasuaki Niizuma, Yutaka Watanuki
    ORNITHOLOGICAL SCIENCE 9 (1) 93 - 100 1347-0558 2010/06 [Refereed][Not invited]
     
    Since parent birds are hypothesized to adjust the level of their nest defense against predators so as to enhance the survival of their offspring, parental nest defense is expected to increase in intensity in relation to increasing clutch size. Empirical studies of bird species, in which clutch sizes have been manipulated artificially, however, have produced results contradicting such expectations, partly, it is thought, because of various errors in experimental design, such as a lack of nesting habitat control, or providing too short a time for parents to assess the value of the manipulated clutch. Hence, further evidence needed to be gathered to clarify whether the basic hypothesis is adequately supported. We manipulated the clutch size of Black-tailed Gulls Larus crassirostris and observed the responses of male parents to a crow decoy in controlled nesting habitats. The intensity of defense was not affected by the clutch size. Opportunities for future reproduction, or constant individual levels of aggressiveness of seem to best explain the observed intensity of nest defense in these long-lived Black-tailed Gulls, rather than the value of the current clutch.
  • Daisuke Ochi, Nariko Oka, Yutaka Watanuki
    JOURNAL OF ETHOLOGY 28 (2) 313 - 321 0289-0771 2010/05 [Refereed][Not invited]
     
    Parents of albatross and shearwater species employ a dual foraging strategy, feeding their chicks quickly in repeated short trips and then restoring their own fuel reserves during longer trips. A decline in parental body condition is believed to trigger longer trips, but chick body condition and age may also play a role. To investigate these factors in the little-studied streaked shearwater Calonectris leucomelas, we monitored the nest attendance of 17 pairs on Mikura Island in 2005 using an automated identification system. We also monitored body mass changes and meal masses of 5 of the 17 pairs using an automated weighing system. Although the birds did not show a clear dual foraging pattern, trip duration varied widely from 1 to 15 days. On average, the birds fed chicks 67.6 g during nighttime meals at 2.74-day intervals. Since meal mass did not depend on trip duration, feeding efficiency (meal mass delivered per unit trip duration) decreased as trip duration increased. Parents accumulated more energy reserves when they took longer trips. Parents appeared likely to initiate longer trips when their body condition declined or chick body condition recovered.
  • C. B. Thaxter, S. Wanless, F. Daunt, M. P. Harris, S. Benvenuti, Y. Watanuki, D. Gremillet, K. C. Hamer
    JOURNAL OF EXPERIMENTAL BIOLOGY 213 (7) 1018 - 1025 0022-0949 2010/04 [Refereed][Not invited]
     
    Species of bird that use their wings for underwater propulsion are thought to face evolutionary trade-offs between flight and diving, leading to the prediction that species with different wing areas relative to body mass (i.e. different wing loadings) also differ in the relative importance of flight and diving activity during foraging trips. We tested this hypothesis for two similarly sized species of Alcidae (common guillemots and razorbills) by using bird-borne devices to examine three-dimensional foraging behaviour at a single colony. Guillemots have 30% higher wing loading than razorbills and, in keeping with this difference, razorbills spent twice as long in flight as a proportion of trip duration whereas guillemots spent twice as long in diving activity. Razorbills made a large number of short, relatively shallow dives and spent little time in the bottom phase of the dive whereas guillemots made fewer dives but frequently attained depths suggesting that they were near the seabed (ca. 35-70. m). The bottom phase of dives by guillemots was relatively long, indicating that they spent considerable time searching for and pursuing prey. Guillemots also spent a greater proportion of each dive bout underwater and had faster rates of descent, indicating that they were more adept at maximising time for pursuit and capture of prey. These differences in foraging behaviour may partly reflect guillemots feeding their chicks single large prey obtained near the bottom and razorbills feeding their chicks multiple prey from the water column. Nonetheless, our data support the notion that interspecific differences in wing loadings of auks reflect an evolutionary trade-off between aerial and underwater locomotion.
  • Nobuo Kokubun, Akinori Takahashi, Motohiro Ito, Kei Matsumoto, Alexander S. Kitaysky, Yutaka Watanuki
    Aquatic Biology 8 (3) 289 - 298 1864-7782 2010/03/16 [Refereed][Not invited]
     
    We studied the foraging behaviour of adult thick-billed murres Uria lomvia as they reared their chicks at St. George Island, Alaska, USA, relative to the thermal structure of the nearby ocean water column in the summers 2004, 2006, and 2007 using data recorders attached to the birds. The thermal structure of the upper ocean varied substantially among the years. Satellite-derived sea surface temperature (SST) and water temperature at depths >40 m were higher in 2004 than in 2006 and 2007 (9.1, 8.3and 7.8°C for mean SST; 5.1, 4.4, and 2.2°C for median bottom temperature, respectively). We recorded a strong thermocline in 2004 and 2007, but not in 2006. Nonetheless, the thermocline was one of the important foraging habitats in all years. The foraging behaviour of thick-billed murres appeared to vary with annual variation in the intensity of the thermocline and water temperature at depth and evidently with associated vertical distribution of prey. Birds spent more time foraging in stratified waters and dived to around thermocline depth (and deeper in 2007) in 2004 and 2007. However, the birds used both stratified and mixed waters in 2006 and were less likely to dive to thermocline depth. Main prey items delivered to chicks varied among years. Sandlance (53% of observed items) and pollock (23%) predominated in 2004, compared with cephalopods (23%), flatfishes (17%) and pollock (15%) in 2006, and cephalopods (62%), pollock (16%) and sculpins (9%) in 2007. © Inter-Research 2010.
  • Motohiro Ito, Akinori Takahashi, Nobuo Kokubun, Alexander S. Kitaysky, Yutaka Watanuki
    Aquatic Biology 8 (3) 279 - 287 1864-7782 2010/03/16 [Refereed][Not invited]
     
    The varying demands associated with egg incubation and chick-rearing are known to have a corresponding effect on the foraging behavior of seabirds. We deployed data loggers on incubating and chick-rearing thick-billed murres Uria lomvia to examine differences in their diving behavior and characteristics of habitats used for foraging. To compare diets of incubating and chickrearing birds we collected their stomach contents using a water offloading technique. We found that incubating birds performed longer foraging trips than chick-rearing birds (incubating: 19.0 ± 7.2 h; chick-rearing: 9.9 ± 5.6 h). Incubating birds foraged in the offshore stratified water masses (sea surface temperature [SST] > 9°C) and frequently dived to the depth of the thermocline (20 to 50 m). Chick-rearing birds spent more time foraging in the inshore, well-mixed water masses (SST < 8°C), and at depths >60 m. Small juvenile walleye pollock Theragra chalcogramma, squid and euphausiids were the dominant prey of incubating and chick-rearing birds. Distributions of these small prey were commonly associated with the thermocline, while larger fish, which parents brought back to feed their chicks, were distributed below the thermocline. Results suggest that incubating murres mainly foraged at shallow depths near the thermocline with higher concentrations of small prey, while chick-rearing murres feed their chicks large prey caught on deep dives while feeding themselves on small prey caught on shallow dives. © Inter-Research 2010.
  • Katsufumi Sato, Kozue Shiomi, Yuuki Watanabe, Yutaka Watanuki, Akinori Takahashi, Paul J. Ponganis
    PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 277 (1682) 707 - 714 0962-8452 2010/03 [Refereed][Not invited]
     
    It has been predicted that geometrically similar animals would swim at the same speed with stroke frequency scaling with mass(-1/3). In the present study, morphological and behavioural data obtained from free-ranging penguins (seven species) were compared. Morphological measurements support the geometrical similarity. However, cruising speeds of 1.8-2.3 m s(-1) were significantly related to mass(0.08) and stroke frequencies were proportional to mass(-0.29). These scaling relationships do not agree with the previous predictions for geometrically similar animals. We propose a theoretical model, considering metabolic cost, work against mechanical forces (drag and buoyancy), pitch angle and dive depth. This new model predicts that: (i) the optimal swim speed, which minimizes the energy cost of transport, is proportional to (basal metabolic rate/drag)(1/3) independent of buoyancy, pitch angle and dive depth; (ii) the optimal speed is related to mass(0.05); and (iii) stroke frequency is proportional to mass(-0.28). The observed scaling relationships of penguins support these predictions, which suggest that breath-hold divers swam optimally to minimize the cost of transport, including mechanical and metabolic energy during dive.
  • Tomohiro Deguchi, Akihiko Wada, Yutaka Watanuki, Yuichi Osa
    ECOLOGICAL RESEARCH 25 (1) 123 - 137 0912-3814 2010/01 [Refereed][Not invited]
     
    Central-place foraging seabirds increase food-loads and decrease meal frequency when they forage in areas that are distant from the breeding colony. In 2001-2002, we studied the seasonal changes in at-sea distribution, food-load mass, meal frequency, and fledging mass in rhinoceros auklets (Cerorhinca monocerata), which forage in coastal waters during the day and feed their chicks at night. In both years, greater numbers of auklets were observed flying in northern waters that are more distant from the colony in June (65 km) and July (65-66 km) than in May (38-47 km). In July of both years, many auklets flew northward across the transect set 65-120 km north of the colony at sunrise; the birds returned south again at sunset, indicating that they foraged in waters outside the study area. This seasonal northward movement of the foraging area may reflect the migration of their main prey item, the Japanese anchovy (Engraulis japonicus), which move with the Tsushima Warm Current flowing from the southern Sea of Japan. Food-load mass did not increase seasonally. In both years, the estimated daily meal frequency was lower in July than in May or June, partly because of the increased foraging distance in July. Late-hatched chicks also displayed lighter fledging masses than early chicks in both years. We suggest that late breeders are required to forage at great distances for longer periods, which may result in decreased meal frequency and lighter fledging mass of their chicks.
  • Yoshihisa Mori, Akinori Takahashi, Philip N. Trathan, Yutaka Watanuki
    AQUATIC BIOLOGY 8 (3) 247 - 257 1864-7790 2010 [Refereed][Not invited]
     
    Diving animals have to counter both drag and buoyancy when moving through the water column. The magnitude of these forces depends upon an animal's swim speed and current depth. Feet, fins or flippers create a motivating force, and different stroke strategies give a variable level of output power, providing both fast swim speeds and reduced travel times to any given target depth. However, while feet, fins or flippers may confer a real advantage, they also create considerable drag and engender high metabolic (oxygen consumption) costs. Consequently, there should be an optimal relationship between output power and stroke frequency during diving. Here we develop diving models to predict the optimal pattern of stroke frequency during both the descent and ascent phase of divers in water, while maintaining a minimum cost of transport (COT, J kg(-1) m(-1)). We also test predictions derived from these models using diving data for foot-propelled South Georgian shags Phalacrocorax georgianus diving to deeper than 80 m. Our predictions include: (1) output power (stroke frequency) should decline during the descent and ascent phases of a dive, but constant output power should be evident when the diving depth is shallow, (2) initial thrust for dives to deeper target depths should be smaller during the descent phase and greater during the ascent phase, and, (3) swim speed should be constant during the descent phase and should decrease first or remain constant, then increase during the ascent phase because of a declining output power strategy. Our empirical data on shags support only some of these predictions. Predictions (1) and (3) were supported by our observations, but Prediction (2) was not, possibly due to unknown but specific factors concerning diving seabirds. These findings suggest that diving seabirds adjust and control their stroke frequency pattern in order to minimize COT during diving, generating the observed changes in swimming speed.
  • Motohiro Ito, Akinori Takahashi, Nobuo Kokubun, Alexander S. Kitaysky, Yutaka Watanuki
    AQUATIC BIOLOGY 8 (3) 279 - 287 1864-7790 2010 [Refereed][Not invited]
     
    The varying demands associated with egg incubation and chick-rearing are known to have a corresponding effect on the foraging behavior of seabirds. We deployed data loggers on incubating and chick-rearing thick-billed murres Uria lomvia to examine differences in their diving behavior and characteristics of habitats used for foraging. To compare diets of incubating and chick-rearing birds we collected their stomach contents using a water offloading technique. We found that incubating birds performed longer foraging trips than chick-rearing birds (incubating: 19.0 +/- 7.2 h; chick-rearing: 9.9 +/- 5.6 h). Incubating birds foraged in the offshore stratified water masses (sea surface temperature [SST] > 9 degrees C) and frequently dived to the depth of the thermocline (20 to 50 m). Chick-rearing birds spent more time foraging in the inshore, well-mixed water masses (SST < 8 degrees C), and at depths >60 m. Small juvenile walleye pollock Theragra chalcogramma, squid and euphausiids were the dominant prey of incubating and chick-rearing birds. Distributions of these small prey were commonly associated with the thermocline, while larger fish, which parents brought back to feed their chicks, were distributed below the thermocline. Results suggest that incubating murres mainly foraged at shallow depths near the thermocline with higher concentrations of small prey, while chick-rearing murres feed their chicks large prey caught on deep dives while feeding themselves on small prey caught on shallow dives.
  • Nobuo Kokubun, Akinori Takahashi, Motohiro Ito, Kei Matsumoto, Alexander S. Kitaysky, Yutaka Watanuki
    AQUATIC BIOLOGY 8 (3) 289 - 298 1864-7790 2010 [Refereed][Not invited]
     
    We studied the foraging behaviour of adult thick-billed murres Uria lomvia as they reared their chicks at St. George Island, Alaska, USA, relative to the thermal structure of the nearby ocean water column in the summers 2004, 2006, and 2007 using data recorders attached to the birds. The thermal structure of the upper ocean varied substantially among the years. Satellite-derived sea surface temperature (SST) and water temperature at depths >40 m were higher in 2004 than in 2006 and 2007 (9.1, 8.3 and 7.8 degrees C for mean SST; 5.1, 4.4, and 2.2 degrees C for median bottom temperature, respectively). We recorded a strong thermocline in 2004 and 2007, but not in 2006. Nonetheless, the thermodine was one of the important foraging habitats in all years. The foraging behaviour of thick-billed murres appeared to vary with annual variation in the intensity of the thermocline and water temperature at depth and evidently with associated vertical distribution of prey. Birds spent more time foraging in stratified waters and dived to around thermocline depth (and deeper in 2007) in 2004 and 2007. However, the birds used both stratified and mixed waters in 2006 and were less likely to dive to thermocline depth. Main prey items delivered to chicks varied among years. Sand lance (53% of observed items) and pollock (23%) predominated in 2004, compared with cephalopods (23%), flatfishes (17%) and pollock (15%) in 2006, and cephalopods (62%), pollock (16%) and sculpins (9%) in 2007.
  • 綿貫豊, 高橋晃周, Trathan PN, Wanless S, 坂本健太郎, 佐藤克文
    日本鳥学会誌 59 20 - 30 2010 [Refereed][Not invited]
  • 風間健太郎, 伊藤元裕, 新妻靖章, 桜井泰憲, 高田秀重, Sydeman WJ, Croxall JP, 綿貫豊
    日本鳥学会誌 59 38 - 54 2010 [Refereed][Not invited]
  • Emma L. Teuten, Jovita M. Saquing, Detlef R. U. Knappe, Morton A. Barlaz, Susanne Jonsson, Annika Bjorn, Steven J. Rowland, Richard C. Thompson, Tamara S. Galloway, Rei Yamashita, Daisuke Ochi, Yutaka Watanuki, Charles Moore, Pham Hung Viet, Touch Seang Tana, Maricar Prudente, Ruchaya Boonyatumanond, Mohamad P. Zakaria, Kongsap Akkhavong, Yuko Ogata, Hisashi Hirai, Satoru Iwasa, Kaoruko Mizukawa, Yuki Hagino, Ayako Imamura, Mahua Saha, Hideshige Takada
    PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 364 (1526) 2027 - 2045 0962-8436 2009/07 [Refereed][Invited]
     
    Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls ( PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2'-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bisphenol A, at concentrations from sub ng g(-1) to mg g(-1). Some of these compounds are added during plastics manufacture, while others adsorb from the surrounding seawater. Concentrations of hydrophobic contaminants adsorbed on plastics showed distinct spatial variations reflecting global pollution patterns. Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride. Both a mathematical model using equilibrium partitioning and experimental data have demonstrated the transfer of contaminants from plastic to organisms. A feeding experiment indicated that PCBs could transfer from contaminated plastics to streaked shearwater chicks. Plasticizers, other plastics additives and constitutional monomers also present potential threats in terrestrial environments because they can leach from waste disposal sites into groundwater and/or surface waters. Leaching and degradation of plasticizers and polymers are complex phenomena dependent on environmental conditions in the landfill and the chemical properties of each additive. Bisphenol A concentrations in leachates from municipal waste disposal sites in tropical Asia ranged from sub mu g l(-1) to mg l(-1) and were correlated with the level of economic development.
  • Sato K, Sakamoto KQ, Watanuki Y, Takahashi A, Katsumata N, Bost CA, Weimerskirch H
    PLoS ONE 4 (4) e5400  1932-6203 2009/04/29 [Refereed][Not invited]
  • TANAKA Yuzan, ITO Motohiro, WATANUKI Yutaka
    Japanese journal of ornithology 日本鳥学会 58 (1) 46 - 54 0913-400X 2009/04/24 [Refereed][Not invited]
  • Kentaro Q. Sakamoto, Katsufumi Sato, Mayumi Ishizuka, Yutaka Watanuki, Akinori Takahashi, Francis Daunt, Sarah Wanless
    PLOS ONE 4 (4) e5370  1932-6203 2009/04 [Refereed][Not invited]
     
    An ethogram is a catalogue of discrete behaviors typically employed by a species. Traditionally animal behavior has been recorded by observing study individuals directly. However, this approach is difficult, often impossible, in the case of behaviors which occur in remote areas and/or at great depth or altitude. The recent development of increasingly sophisticated, animal-borne data loggers, has started to overcome this problem. Accelerometers are particularly useful in this respect because they can record the dynamic motion of a body in e. g. flight, walking, or swimming. However, classifying behavior using body acceleration characteristics typically requires prior knowledge of the behavior of free-ranging animals. Here, we demonstrate an automated procedure to categorize behavior from body acceleration, together with the release of a user-friendly computer application, "Ethographer''. We evaluated its performance using longitudinal acceleration data collected from a foot-propelled diving seabird, the European shag, Phalacrocorax aristotelis. The time series data were converted into a spectrum by continuous wavelet transformation. Then, each second of the spectrum was categorized into one of 20 behavior groups by unsupervised cluster analysis, using k-means methods. The typical behaviors extracted were characterized by the periodicities of body acceleration. Each categorized behavior was assumed to correspond to when the bird was on land, in flight, on the sea surface, diving and so on. The behaviors classified by the procedures accorded well with those independently defined from depth profiles. Because our approach is performed by unsupervised computation of the data, it has the potential to detect previously unknown types of behavior and unknown sequences of some behaviors.
  • Motohiro Ito, Hiroshi Minami, Yuzan Tanaka, Yutaka Watanuki
    MARINE ECOLOGY PROGRESS SERIES 393 273 - 284 0171-8630 2009 [Refereed][Not invited]
     
    The structure of a marine food web can change quickly within seasons as well as interannually in response to physical oceanographic changes. In this study, we examined the relationship between temporal changes in the marine ecosystem of northern Hokkaido, Japan, and diets of rhinoceros auklets Cerorhinca monocerata breeding in this region. To obtain an integrated measure of changes in diet composition on short (days) and inter-annual (2004 and 2005) time scales, we used a 2-pronged approach. We examined (1) the diets of adults using stomach contents and stable isotope signatures in tissues, and (2) chick diets using the composition of bill-loads delivered to chicks. During the incubation period, the diet of adults comprised euphausiids (Thysanoessa longipes and T inermis). During the chick-rearing period, the diet of adults was age 0 Japanese sandlance Ammodytes personatus and age 0 Japan Sea greenling Pleurogrammus azonus in the early period, but switched quickly (<10 d) to warm-water-pref erring Japanese anchovy Engraulis japonicus when the warm Tsushima Current intruded into their foraging range. Adult blood plasma stable isotope ratios reflected these seasonal changes in stomach content. Diets did not differ between age categories. Furthermore, the timing of diet switching to anchovy differed inter-annually, and was about 10 d later in 2005 than 2004, reflecting a difference in the timing of the intrusion of warm water. We conclude that rhinoceros auklets respond sensitively to current-related rapid marine food web changes.
  • Scaling of soaring seabirds and implications for maximum body size in albatross-like flyers
    Sato K, Sakamoto KQ, Watanuki Y, Takahashi A, Katsumata N, Bost C.-A, Weimerskirch H
    PLoS One 4 e5400  2009 [Refereed][Not invited]
  • Naoki Tomita, Yasuaki Niizuma, Masaoki Takagi, Motohiro Ito, Yutaka Watanuki
    ECOLOGICAL RESEARCH 24 (1) 157 - 162 0912-3814 2009/01 [Refereed][Not invited]
     
    Sea-surface temperature (SST) directly and indirectly affects the distribution and abundance of prey species for seabirds, so we expect variation in SST to be associated with variation in seabird life history traits. In black-tailed gulls (Larus crassirostris) at Teuri Island in northern Hokkaido, Japan, we investigated the diet of the gulls prior to egg laying in 2004 and 2005, and examined the influences of SST in March or April, when the gulls congregate in the colony, on egg-laying parameters using 13 years of data (1992-2004). The gulls fed on krill (Thysanoessa inermis) and fish prior to the egg laying. Mean first egg dates and clutch sizes were significantly and quadratically related to SST anomalies in March, but were not influenced by SST anomalies in April. There was no significant effect of SSTs in either March or April on egg volume. Sea-surface temperature anomalies in March of the years of early laying (-1 to 1A degrees C) were higher than those in 2001 (-2.2A degrees C), but lower than those in 1992 (+1.2A degrees C) and 2004 (+1.1A degrees C). Thysanoessa inermis congregates to spawn at the sea surface, when SSTs rise 3-4A degrees C. Thus, a mismatch between food availability and the timing of egg production in the gulls could have occurred in these 3 years. This study suggests that SST fluctuations prior to laying are important in breeding success of black-tailed gulls.
  • Chris B. Thaxter, Francis Daunt, Keith C. Hamer, Yutaka Watanuki, Mike P. Harris, David Gremillet, Gerrit Peters, Sarah Wanless
    JOURNAL OF AVIAN BIOLOGY 40 (1) 75 - 84 0908-8857 2009/01 [Refereed][Not invited]
     
    Sexual differences in food provisioning rates of monomorphic seabirds are well known but poorly understood. Here, we address three hypotheses that attempt to explain female-biased food provisioning in common guillemots Uria aalge: (1) males spend more time in nest defence, (2) females have greater foraging efficiency, and (3) males allocate a greater proportion of foraging effort to self-maintenance. We found that males spent no more time with chicks than females but made longer trips and travelled further from the colony. There was extensive overlap between sexes in core foraging areas, indicating that females were not excluding males from feeding opportunities close to the colony. However, as a result of their longer trips, the total foraging areas of males were much greater than those of females. There was no difference between sexes in overall dive rate per hour at sea, in behaviour during individual dives or in a number of other measures of foraging efficiency including the frequency, depth and duration of dives and the dive: pause ratio during the final dive bout of each trip, which was presumably used by both sexes to obtain prey for the chick. These data strongly suggest that sexes did not differ in their ability to locate and capture prey. Yet males made almost twice as many dives per trip as females, suggesting that males made more dives than females for their own benefit. These results support the hypothesis that female-biased food provisioning arose from a difference between sexes in the allocation of foraging effort between parents and offspring, in anticipation of a prolonged period of male-only post-fledging care of the chick, and not from differences in foraging efficiency or time spent in nest defence.
  • 井上裕紀子, 出口智広, 越智大介, 綿貫 豊, 岡 奈理子
    日本鳥学会誌 58 65 - 72 2009 [Refereed][Not invited]
  • Yutaka Watanuki, Motohiro Ito, Tomohiro Deguchi, Shoshiro Minobe
    MARINE ECOLOGY PROGRESS SERIES 393 259 - 271 0171-8630 2009 [Refereed][Invited]
     
    Predator-prey relationships are key to understanding complex marine ecosystem dynamics. The match-mismatch hypothesis posits that predators time energy-intensive activities, such as reproduction, to periods of high food availability. However, predators may be constrained by various ecological or physiological processes, leading to mistimed activities relative to prey availability. We investigated inter-annual variation in the timing of breeding for a piscivorous seabird (rhinoceros auklet Cerorhinca monocerata) in relation to availability of a preferred prey item, Japanese anchovy Engraulis japonicus, using data collected over 18 yr between 1984 and 2006 at Teuri Island in the northern Japan Sea. Our primary goals were (1) to identify the climatic factors that affect the seabirds' timing of breeding, proxied by hatching date, and anchovy seasonal availability, and (2) to quantify the fitness effects of predator-prey matches and mismatches relative to climate variability. Hatching date was later in years with lower spring air temperatures. Auklets switched their feeding from sandlance and juvenile greenling to anchovy when it was transported into the birds' foraging range with the seasonal northern expansion of 13 degrees C warm water from the south. The mismatch between hatching date and the period of high anchovy availability was most pronounced when spring air temperatures were warm, and there was a weak Tsushima (warm) Current. Spring air temperature was influenced by spring atmospheric pressure gradients in the Arctic and northern Eurasia, which drive the east Asian winter monsoon, whereas timing of the Tsushima warm water expansion was influenced by winter surface pressures over the western North Pacific. Chick growth rates, mass at fledging, and overall fledging success (fitness) were lower during mismatch years when the auklets fed less on anchovy. The auklets were constrained to adjust hatching date because the seasonal mismatch appeared to be driven by independent and unpredictable surface pressure patterns.
  • Julie A. Thayer, Douglas F. Bertram, Scott A. Hatch, Mark J. Hipfner, Leslie Slater, William J. Sydeman, Yutaka Watanuki
    CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES 65 (8) 1610 - 1622 0706-652X 2008/08 [Refereed][Not invited]
     
    We tested the hypothesis of synchronous interannual changes in forage fish dynamics around the North Pacific Rim. To do this, we sampled forage fish communities using a seabird predator, the rhinoceros anklet (Cerorhinca monocerata), at six coastal study sites from Japan to California. We investigated whether take of forage fishes was related to local marine conditions as indexed by sea surface temperature (SST). SST was concordant across sites in the eastern Pacific, but inversely correlated between east and west. Forage fish Communities consisted of anchovy (Engraulis spp.), sandlance (Ammodytes spp.), capelin (Mallotus spp.). and juvenile rockfish (Sebastes spp.), among others, and take of forage fish varied in response to interannual and possibly lower-frequency oceanographic variability. Take of primary forage species were significantly related to changes in SST only at the eastern sites. We found synchrony in interannual variation of primary forage fishes across several regions in the eastern Pacific, but no significant east-west correlations. Specifically in the Japan Sea, factors other than local SST or interannual variability may more strongly influence forage fishes. Predator diet sampling offers a fishery-independent. large-scale perspective on forage fish dynamics that may be difficult to obtain using conventional means of study.
  • Akinori Takahashi, Kei Matsumoto, George L. Hunt, Michael T. Shultz, Alexander S. Kitaysky, Katsufumi Sato, Kohji Iida, Yutaka Watanuki
    DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY 55 (16-17) 1837 - 1845 0967-0645 2008/08 [Refereed][Invited]
     
    Linking diving and foraging behavior of small seabirds with the fine-scale characteristics of water masses has been challenging largely due to sampling constraints. We examined the diving behavior of 12 chick-rearing thick-billed murres (Uria lomvia) at St. George Island, southeastern Bering Sea, in relation to sea-surface temperature (SST) and thermocline depth using ventrally attached depth-temperature-acceleration data loggers. Our results from summer 2004 showed that murres swam in water masses ranging from well-mixed (SST 7-9 degrees C, estimated distance of 14 km from the breeding colony) to well-stratified (SST 9-12 degrees C, estimated distance of 30-50 km). Murres dove deeper (modal depth: 60-70 m) in the mixed water mass than in the stratified water, where most dives were to just below the thermocline depth (modal depth: 20-30 m). We suggest that the thermocline is important in shaping dive profiles of thick-billed murres, possibly through its effect on the vertical distribution of both zooplankton and fish prey. (C) 2008 Elsevier Ltd. All rights reserved.
  • Katsufumi Sato, Francis Daunt, Yutaka Watanuki, Akinori Takahashi, Sarah Wanless
    JOURNAL OF EXPERIMENTAL BIOLOGY 211 (1) 58 - 65 0022-0949 2008/01 [Refereed][Not invited]
     
    To understand the foraging strategies of free-ranging diving animals, time series information on both foraging effort and foraging success is essential. Theory suggests that wing stroke frequency for aerial flight should be higher in heavier birds. Based on this premise, we developed a new methodology using animal-borne accelerometers to estimate fine-scale temporal changes in body mass of a pursuit-diving, piscivorous seabird, the European shag, Phalacrocorax aristotelis. We hypothesized that variations in body mass determined from changes in wing stroke frequency before and after a series of dives would be related to the amount of prey captured. The estimated net gain in body mass during a foraging trip was highly variable, ranging from -30 to 260 g, values that were extremely similar to food loads obtained from shags on the Isle of May in previous years using water-offloading and nest balances. Load sizes estimated using the wing stroke method were strongly and positively related to both cumulative flight time and return flight time. At the trip level, load size was unrelated to cumulative dive bout duration and the total amount of time spent underwater. However, highly significant relationships were apparent at the individual bout level, with birds showing bigger mass gains following longer dive bouts. Results from this study are therefore extremely encouraging and suggest that changes in body mass determined from changes in wing stroke frequency may provide a reliable method of obtaining short- to medium-term information on foraging effort and success of diving seabirds.
  • Responses in breeding behaviour of Black-tailed gull Laris crassirostris to different marine environments.
    Kazama K, Tomita N, Ito M, Niizuma Y, Takagi M, Watanuki Y
    Proceedings of International Symposium, The Origin and Evolution of Natural Diversity 215 - 220 2008 [Not refereed][Invited]
  • 風間健太郎, 坂本健太郎, 綿貫豊
    山階鳥類研究所研究報告 39 112 - 116 2008 [Refereed][Not invited]
  • 田中遊山, 本田聡, 磯田豊, 伊藤元裕, 綿貫豊
    日本鳥学会誌 57 148 - 153 2008 [Refereed][Not invited]
  • Diet and foraging habitat of Leach’s Storm-petrels breeding at Daikoku Island, Japan
    Niizuma Y, Toge Y, Manabe Y, Sawada M, Yamamura O, Watanuki Y
    Proceedings of International Symposium, The Origin and Evolution of Natural Diversity 153 - 160 2008 [Not refereed][Invited]
  • Matsumoto K, Deguchi T, Wada A, Kato A, Saito S, Watanuki Y
    Ornithological Science 7 37 - 46 2008 [Refereed][Not invited]
  • Yutaka Watanuki, Francis Daunt, Akinori Takahashi, Mark Newei, Sarah Wanless, Katsufumi Sat, Nobuyuki Miyazaki
    MARINE ECOLOGY PROGRESS SERIES 356 283 - 293 0171-8630 2008 [Refereed][Not invited]
     
    Studies of the fine-scale use of foraging habitat are essential for understanding the role of seabirds in marine ecosystems. However, until recently, relationships between foraging and habitat usage were only possible at a coarse scale. We used miniaturized bird-borne digital still-picture camera loggers to obtain high-quality images of the foraging habitat used by 9 European shags Phalacrocorax aristotelis. Underwater images revealed that shags are almost exclusively benthic feeders, but used 2 very distinct foraging habitats: sandy areas and rocky areas with brittlestars, soft corals and kelp. We found no evidence that individuals specialize on a particular habitat. Birds were recorded in rocky and sandy areas over the course of a day and in some cases within a trip. foraging behaviour differed markedly between habitats. In rocky areas birds foraged solitarily, over a wide range of depths (10 to 40 m) and travelled along the bottom while searching for bottom-living fish such as butterfish Pholis gunnellus. In contrast, shags using sandy habitat frequently fed with conspecifics, foraged mainly at 2 depths (24 or 32 m) and spent the bottom phase of the dive probing into the sand with their bill, presumably to catch lesser sandeels Ammodytes marinus, the major prey item in the diet. This study highlights the flexible foraging strategy of European shags and illustrates how image and dive data can be combined to improve our understanding of the factors influencing the foraging success of benthic feeders.
  • Watanuki Y, Sato K
    Ornithological Science 7 15 - 28 2008 [Refereed][Not invited]
  • Takahashi A, Ochi D, Watanuki Y, Deguchi T, Oka N, Afanasyev V, Fox JW, Trathan P
    Ornithological Science 7 29 - 35 2008 [Refereed][Not invited]
  • 伊藤元裕, 綿貫豊
    日本鳥学会誌 57 140 - 147 2008 [Refereed][Not invited]
  • 越智大介, 綿貫豊
    日本鳥学会誌 57 133 - 139 2008 [Refereed][Not invited]
  • Rei Yamashita, Hideshige Takada, Michio Murakami, Masa-Aki Fukuwaka, Yutaka Watanuki
    ENVIRONMENTAL SCIENCE & TECHNOLOGY 41 (14) 4901 - 4906 0013-936X 2007/07 [Refereed][Not invited]
     
    Oil secreted from the preen gland (located at the base of the tail feathers) of seabirds can be collected from live birds. We determined PCB concentrations and profiles in the preen gland oil and corresponding abdominal adipose tissue collected from 30 seabirds (2 orders, 3 families, 10 genera, 13 species) to examine the utility of the oil as a monitoring medium. Samples were collected from seabirds that had died in traffic accidents or had become caught unintentionally in experimental drift nets and long-lines in the North Pacific Ocean. Significant concentrations of PCBs were detected in all oil samples, with a concentration range of 9-4834 ng/g-lipid and a geometric mean of 404 ng/g-lipid. PCBs in the oil had more lower-chlorinated congeners than those in corresponding abdominal adipose, suggesting that they had less opportunity to undergo metabolism before they were secreted from the gland. We observed a weak but significant correlation between the PCB concentrations in the oil and abdominal adipose tissue (R-2 = 0.19, P < 0.05). Correcting for the metabolic loss of PCBs on the basis of congener profiles improved the correlation (R2 = 0.48, P < 0.001), implying that congener-specific determination of PCBs in the preen gland oil enables us to estimate PCB concentrations in the abdominal adipose within 1 order of magnitude difference. The differences in PCB concentrations among the 13 species are discussed in terms of dietary behavior, habitat, and migration.
  • Yasuaki Niizuma, Geir W. Gabrielsen, Katsufumi Sato, Yutaka Watanuki, Yasuhiko Naito
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY 147 (2) 438 - 444 1095-6433 2007/06 [Refereed][Not invited]
     
    A major challenge for diving birds, reptiles, and mammals is regulating body temperature while conserving oxygen through a reduction in metabolic processes. To gain insight into how these needs are met, we measured dive depth and body temperatures at the core or periphery between the skin and abdominal muscles simultaneously in freely diving Brunnich's guillemots (Uria lomvia), an arctic seabird, using an implantable data logger (16-mm diameter, 50-mm length, 14-g mass, Little Leonardo Ltd., Tokyo). Guillemots exhibited increased body core temperatures, but decreased peripheral temperatures, during diving. Heat conservation within the body core appeared to result from the combined effect of peripheral vasoconstriction and a high wing beat frequency that generates heat. Conversely, the observed tissue hypothermia in the periphery should reduce metabolic processes as well as heat loss to the water. These physiological effects are likely one of the key physiological adaptations that makes guillemots to perform as an efficient predator in arctic waters. (c) 2007 Elsevier Inc. All rights reserved.
  • Katsufumi Sato, Yutaka Watanuki, Akinori Takahashi, Patrick J. O. Miller, Hideji Tanaka, Ryo Kawabe, Paul J. Ponganis, Yves Handrich, Tomonari Akamatsu, Yuuki Watanabe, Yoko Mitani, Daniel P. Costa, Charles-Andre Bost, Kagari Aoki, Masao Amano, Phil Trathan, Ari Shapiro, Yasuhiko Naito
    PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 274 (1609) 471 - 477 0962-8452 2007/02 [Refereed][Not invited]
     
    It is obvious, at least qualitatively, that small animals move their locomotory apparatus faster than large animals: small insects move their wings invisibly fast, while large birds flap their wings slowly. However, quantitative observations have been difficult to obtain from free-ranging swimming animals. We surveyed the swimming behaviour of animals ranging from 0.5 kg seabirds to 30 000 kg sperm whales using animal-borne accelerometers. Dominant stroke cycle frequencies of swimming specialist seabirds and marine mammals were proportional to mass(-0.29) (R-2=0.99, n=17 groups), while propulsive swimming speeds of 1-2 m s(-1) were independent of body size. This scaling relationship, obtained from breath-hold divers expected to swim optimally to conserve oxygen, does not agree with recent theoretical predictions for optimal swimming. Seabirds that use their wings for both swimming and flying stroked at a lower frequency than other swimming specialists of the same size, suggesting a morphological trade-off with wing size and stroke frequency representing a compromise. In contrast, foot-propelled diving birds such as shags had similar stroke frequencies as other swimming specialists. These results suggest that muscle characteristics may constrain swimming during cruising travel, with convergence among diving specialists in the proportions and contraction rates of propulsive muscles.
  • Underwater images from bird-borne cameras provide clue to poor breeding success of European Shags in 2005
    Watanuki Y, Takahashi A, Daunt F, Sato K, Miyazaki N, Wanless S
    British Birds 100 466 - 470 2007 [Not refereed][Not invited]
  • Y Watanuki, S Wanless, M Harris, Lovvorn, JR, M Miyazaki, H Tanaka, K Sato
    JOURNAL OF EXPERIMENTAL BIOLOGY 209 (7) 1217 - 1230 0022-0949 2006/04 [Refereed][Not invited]
     
    In diving birds, the volume and resulting buoyancy of air spaces changes with dive depth, and hydrodynamic drag varies with swim speed. These factors are important in the dive patterns and locomotion of alcids that use their wings both for aerial flight and underwater swimming and of penguins that use their wings only for swimming. Using small data-loggers on free-ranging birds diving to 20-30 m depth, we measured depth at 1 Hz and surge and heave accelerations at 32-64 Hz of four species of alcids (0.6-1.0 kg mass) and the smallest penguin species (1.2 kg). Low- and high-frequency components of the fluctuation of acceleration yielded estimates of body angles and stroke frequencies, respectively. Swim speed was estimated from body angle and rate of depth change. Brunnich's (Uria lomvia) and common (Uria aalge) guillemots descended almost vertically, whereas descent of razorbills (Alca torda), rhinoceros auklets (Cerorhinca monocerata) and little penguins (Eudyptula minor) was more oblique. For all species, swim speed during descent was within a relatively narrow range. Above depths of 20-30 m, where they were all positively buoyant, all species ascended without wing stroking. During descent, little penguins made forward accelerations on both the upstroke and downstroke regardless of dive depth. By contrast, descending alcids produced forward accelerations on both upstroke and downstroke at depths of <10 m but mainly on the downstroke at greater depths; this change seemed to correspond to the decrease of buoyancy with increasing depth. The magnitude of surge (forward) acceleration during downstrokes was smaller, and that during upstrokes greater, in little penguins than in alcids. This pattern presumably reflected the proportionally greater mass of upstroke muscles in penguins compared with alcids and may allow little penguins to swim at less variable instantaneous speeds.
  • The minimum air volume kept in diving Adélie Penguins: evidence for regulation of air volume in the respiratory system.
    Sato K, Watanuki Y, Naito Y
    Coastal Marine Science 30 439 - 442 2006 [Not refereed][Not invited]
  • 越智大介, 松本経, 綿貫豊, 岡奈理子
    日本鳥学会誌 55 24 - 28 2006 [Refereed][Not invited]
  • M Takenaka, Y Niizuma, Y Watanuki
    CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE 83 (11) 1476 - 1485 0008-4301 2005/11 [Refereed][Not invited]
     
    By manipulating meal size and frequency in an alcid, the rhinoceros auklet (Cerorhinca monocerata (Pallas, 1811)), we examined two hypotheses: (1) poorly fed chicks allocate resources preferentially to developing organs essential for fledging, and (2) intermittently fed chicks deposit more lipids than regularly fed ones. Chicks were fed normal (NORMAL; 40-80 g, mean meal mass in a normal year), small (LOW; 26-54 g, half of NORMAL), or large (HIGH; 80-160 g, twice as much as NORMAL) amounts of sandlance (Ammodytes personatus Girard, 1856) every day or the large meal (80-160 g) every 2 days (INTERMITTENT). Chicks fed more food grew faster. The HIGH group had the greatest fledging mass and shortest fledging period. The wingspan and brain mass of fledglings did not differ among groups. The heart, liver, and breast muscle at fledging were 15%-25% smaller in the LOW group than in the NORMAL group but did not differ between the NORMAL and HIGH groups. The total lipid was 43% greater in the HIGH group than in the NORMAL group, and that of the LOW group was 38% smaller. The INTERMITTENT group had a similar lipid mass to the NORMAL group. Chicks feeding on small meals seemed to maintain the growth of organs essential for fledging, while chicks feeding on large meals seemed to deposit a surplus as lipid rather than allocate more to the development of organs.
  • Y Niizuma, M Takagi, M Senda, M Chochi, Y Watanuki
    JOURNAL OF AVIAN BIOLOGY 36 (5) 421 - 427 0908-8857 2005/09 [Refereed][Not invited]
     
    Factors determining clutch size of birds have long been the central issue in studies in life histories. It is assumed that the configuration of brood patches could limit the maximum clutch size. To test this hypothesis we manipulated clutch sizes and measured egg temperature as well as reproductive consequences in black-tailed gulls Larus crassirostris, which usually lay two egg clutches and have three brood patches. Mean egg temperature in 4-egg clutches (32.6 +/- 1.0 degrees C) was significantly lower than in 2-egg (34.6 +/- 0.4 degrees C) and 3-egg clutches (34.1 +/- 0.4 degrees C), because egg temperature of the coolest egg within a 4-egg clutch was often substantially lower than the other three eggs. The proportion of eggs hatching from 4-egg clutches (11.6%) was lower than those of 2-egg (49.1%) and 3-egg clutches (52.0%). Four-egg clutches had longer incubation periods (29.6 +/- 1.3 day) than 2-egg (28.1 +/- 1.7 day) and 3-egg clutches (28.0 +/- 1.3 day). The results indicate that incubation capacity, which may be determined by the configuration of brood patches, limits the maximum clutch size in black tailed gulls, but not the actual clutch size typically laid.
  • Y Watanuki, A Takahashi, F Daunt, S Wanless, M Harris, K Sato, Y Naito
    JOURNAL OF EXPERIMENTAL BIOLOGY 208 (12) 2207 - 2216 0022-0949 2005/06 [Refereed][Not invited]
     
    Bottom-feeding, breath-hold divers would be expected to minimize transit time between the surface and foraging depth, thus maximizing the opportunities for prey capture during the bottom phase of the dive. To achieve this they can potentially adjust a variety of dive parameters, including dive angle and swim speed. However, because of predictable changes in buoyancy with depth, individuals would also be expected to adjust dive behavior according to dive depth. To test these predictions we deployed miniature, dorsally attached data-loggers that recorded surge and heave accelerations at 64 Hz to obtain the first detailed measurements of a foot-propelled diving bird, the European shag Phalacrocorax aristotelis, in the wild. The results were used to investigate biomechanical changes during the descent, ascent and bottom phases for dives varying between 7 in and 43 in deep. Shags descended and ascended almost vertically (60-90 degrees relative to the sea surface). During descent, swim speed varied between 1.2-1.8 in s(-1) and the frequency of the foot stroke used for propulsion decreased significantly with depth, mainly due to a fivefold increase in the duration of the glide between strokes. Birds appeared to maintain the duration and the maximum strength of power stroke and thus optimize muscle contraction efficiency.
  • T Deguchi, Y Watanuki
    IBIS 147 (1) 217 - 220 0019-1019 2005/01 [Refereed][Not invited]
  • Prefledging mass recession and timing of fledging in Rhinoceros auklets
    Tomohiro Deguchi, Yutaka Watanuki
    Ibis 147 267 - 275 2005 [Not refereed][Not invited]
  • Lovvorn, JR, Y Watanuki, A Kato, Y Naito, GA Liggins
    JOURNAL OF EXPERIMENTAL BIOLOGY 207 (26) 4679 - 4695 0022-0949 2004/12 [Refereed][Not invited]
     
    Loggers were attached to free-ranging Brunnich's guillemots Uria lomvia during dives, to measure swim speeds, body angles, stroke rates, stroke and glide durations, and acceleration patterns within strokes, and the data were used to model the mechanical costs of propelling the body fuselage (head and trunk excluding wings). During vertical dives to 102-135 m, guillemots regulated their speed during descent and much of ascent to about 1.6 +/- 0.2 m s(-1). Stroke rate declined very gradually with depth, with little or no gliding between strokes. Entire strokes from 2 m to 20 m depth had similar forward thrust on upstroke vs downstroke, whereas at deeper depths and during horizontal swimming there was much greater thrust on the downstroke. Despite this distinct transition, these differences had small effect (<6%) on our estimates of mechanical cost to propel the body fuselage, which did not include drag of the wings. Work stroke(-1) was quite high as speed increased dramatically in the first 5 m of descent against high buoyancy. Thereafter, speed and associated drag increased gradually as buoyancy slowly declined, so that mechancal work stroke(-1) during the rest of descent stayed relatively constant. Similar work stroke(-1) was maintained during non-pursuit swimming at the bottom, and during powered ascent to the depth of neutral buoyancy (about 71 m). Even with adjustments in respiratory air volume of +/- 60%, modeled work against buoyancy was important mainly in the top 15 m of descent, after which almost all work was against drag. Drag was in fact underestimated, as our values did not include enhancement of drag by altered flow around active swimmers. With increasing buoyancy during ascent above 71 m, stroke rate, glide periods, stroke acceleration patterns, body angle and work stroke(-1) were far more variable than during descent; however, mean speed remained fairly constant until buoyancy increased rapidly near the surface. For dives to depths >20 m, drag is by far the main component of mechanical work for these diving birds, and speed may be regulated to keep work against drag within a relatively narrow range.
  • Y Watanuki, K Ishikawa, A Takahashi, A Kato
    MARINE BIOLOGY 145 (3) 427 - 434 0025-3162 2004/09 [Refereed][Not invited]
     
    To examine the behavioral adjustment of a generalist marine top predator to variability of their prey, we studied the foraging behavior of Japanese cormorants (Phalacrocorax filamentosus) breeding at Teuri Island, Hokkaido, in years of contrasting demersal and epipelagic prey composition. We used radio telemetry and ship-based surveys to determine behavior and at-sea distribution during three summers (1996-1998). The cormorants fed on epipelagic anchovy (Engraulis Japonicus) and sandlance (Ammodytes personatus) in 1998 (year of epipelagic diet), while they fed on benthic rock fish (Sebastes spp.) and flatfish (Pleuronectidae) and nearshore-living naked sandlance (Hypophychus dybowskii), as well as epibenthic greenling (Hexagrammidae) in 1996 and 1997 (year of demersal diet). Cormorants engaged in larger feeding groups, visited more feeding sites, and stayed at each feeding site for a shorter period in the year of epipelagic diet than in the years of demersal diet. The cormorants made long foraging trips and fed in the mainland coastal habitat, distant from the colony, in the years of demersal diet. Individual radio-tracked birds fed over the wide area between the islands and mainland, in the year of epipelagic diet, while most individuals specialized in mainland or island coastal habitats in the years of demersal diet. Behavioral adjustment of Japanese cormorants might allow them to exploit both unpredictable epipelagic and predictable benthic prey efficiently.
  • Proximate factors determining age and mass at fledging in Rhinoceros Auklets (Cerorhinca monocerata): Intra-and interyear variations
    T Deguchi, A Takahashi, Y Watanuki
    AUK 121 (2) 452 - 462 0004-8038 2004/04 [Refereed][Not invited]
     
    In alcids, growth rate and hatching date of chicks appear to affect fledging age and mass. Underlying mechanisms are hypothesized to be (1) critical wing length at fledging for postfledging survival, (2) synchronization of fledging to dilute predation risk, and (3) variable parental provisioning according to timing of breeding. To elucidate the effects of growth rate and hatching date on fledging age and mass, and to test those mechanistic hypotheses, we measured chick growth and fledging periods in Rhinoceros Auklets (Cerorhinca monocerata) at Teuri Island from 1995 to 2000. The multiple-linear regression analysis showed that intrayear variations of fledging age and mass were explained by growth rate or hatching date in five out of six years. Faster-growing chicks fledged younger and heavier, and earlier-hatched chicks fledged older and heavier. Consequently, no apparent correlation between fledging age and mass was observed in five out of six years. Analysis of interyear variation showed a negative correlation between fledging age and mass, which indicates that growth rates rather than hatching dates had a major effect. Wing length at fledging was independent of growth in mass. More than 80% of chicks fledged when they attained a narrow range of wing length (130-150 mm), presumably because they remained in their nests until they attained the critical wing length. In five out of six years, the chicks did not synchronize timing of fledging relative to timing of hatching. Later-hatched chicks attained lighter peak masses and at younger ages, which may indicate that their parents decreased provisioning rates when the chicks were still young. We suggest that (1) critical wing length at fledging and (2) variable parental provisioning according to timing of breeding could be underlying mechanisms determining these relationships between fledging age and mass.
  • A Takahashi, K Sato, J Nishikawa, Y Watanuki, Y Naito
    JOURNAL OF ETHOLOGY 22 (1) 5 - 11 0289-0771 2004/01 [Refereed][Not invited]
     
    Synchronizing behavior with other conspecifics has been suggested as serving a function of increased foraging efficiency. However, the potential costs associated with synchronization of behavior have rarely been studied. Adelie penguins Pygoscelis adeliae sometimes dive synchronously in small open waters surrounded by fast sea ice. We examined the diving behavior of three couples and one trio, which were observed to dive synchronously among groups of 12-47 birds for 1.7-4.5 h duration, with time-depth recorders. Timing of diving and surfacing differed slightly between individuals, and one bird tended to initiate diving earlier than the other. Although the duration of the dives differed only slightly between these birds, the maximum depth of the dives differed to a large extent, with one member tending to dive consistently deeper than the other bird in two out of the four cases. Vertical distances between tagged birds in the undulatory phases of the dives (presumed feeding time) were greater than those in the descent and ascent phases, suggesting independent foraging by group members. Duration of the undulatory phase of the dives tended to be shorter in deeper-diving individuals than the others in the synchronously diving group, suggesting a potential cost of reduced feeding time to synchronize diving and surfacing with other birds. A digital video image relating to the article is available at http://www.momo-p.com/showdetail-e.php?movieid=momo030605pa01a.
  • Y Watanuki, A Takahashi, K Sato, A Kato, CA Bost
    JOURNAL OF ETHOLOGY 22 (1) 91 - 98 0289-0771 2004/01 [Refereed][Not invited]
     
    Among colonies with different foraging distances, central-place-foraging seabirds may change their foraging and reproductive efforts. We compared the body condition, meal frequency, and diving behavior of male and female Adelie penguins at two locations: Dumont d'Urville, where there was little sea ice and they foraged in open waters far from the colony; and Syowa, where there was heavy, fast sea ice and they foraged in ice cracks close to the colony. The parental mass decrease rate during the chick-rearing period was similar between colonies and between sexes. A large individual variation in meal frequency positively affected the brood growth rate, but daily underwater time did not. A weak but significant positive effect of body condition on brood growth rate was found only in males at Syowa. It was suggested that males work with better body condition than females. We propose the hypothesis that the regional difference in the distance to the feeding sites and the sex difference in body energy reserve might constrain the capacity to regulate reproductive effort.
  • 綿貫豊
    日本鳥学会誌 53 1 - 10 2004 [Refereed][Not invited]
  • T Deguchi, Y Watanuki, Y Niizuma, A Nakata
    PROGRESS IN OCEANOGRAPHY 61 (2-4) 267 - 275 0079-6611 2004 [Refereed][Not invited]
     
    The diets of breeding seabirds can be a good monitor of marine environmental changes. From 1984 to 2001 we monitored the diets of black-tailed gulls (Larus crassirostris) ("surface foragers"), rhinoceros auklets (Cerorhinca monocerata) ("epipelagic divers"), and Japanese cormorants (Phalacrocorax filamentotus) ("bottom divers") that breed on Teuri Island at the northern boundary of the Tsushima Warm current in the Sea of Japan/East Sea. Between 1984 and 1987, both the gulls and the auklets foraged on the sardine (Sardinops melanostictus), but after 1992, they switched to the anchovy (Engraulis japonica). This change might reflect the collapse of the sardine stock in the late 1980s. In the 1990s, the year-to-year variations of the percentage of anchovy in the diets of the three seabird species showed similar trends: High in 1994 and 1998-2001; and low in 1992-1993 and 1995-1997. The estimated stock size of the anchovy population in the Tsushima Current area was positively correlated with the percentage of mass of anchovy in the seabirds' diets. Thus, the short-term annual changes of the total anchovy availability, which might reflect SST or the volume transport of Tsushima Current, possibly affected the seabirds diets on this island. (C) 2004 Elsevier Ltd. All rights reserved.
  • Proximate factors determining the age and mass of fledging in rhinoceros auklets: variations within and among years.
    Deguchi T, Takahashi A, Watanuki Y
    Auk 121, 452-462.  2004 [Refereed][Not invited]
  • Y Watanuki, A Takahashi, K Sato
    IBIS 145 (4) 558 - 564 0019-1019 2003/10 [Refereed][Not invited]
     
    Individual feeding area specialization has been reported for several seabird species. Researchers suspect that this behaviour results in feeding and/or reproductive advantages. Adelie Penguins Pygoscelis adeliae feed in small predictable open waters in a fast sea-ice area near Syowa Station, Antarctica. Their feeding sites were determined by radiotracking both members of 20 pairs rearing chicks. Twenty-five birds repeatedly fed in distinct areas more frequently than expected by chance, while the remaining 15 birds had no significant feeding area specialization. Birds seemed to feed at sites that were closer to their most recent feeding sites than they were to earlier feeding sites. Variation in specialized area, degree of feeding area fidelity and distance to feeding sites had no significant effect on the number of feeds that a bird brought to chicks per day. Neither did the estimated mass of feeds brought per day per pair depend on feeding area specialization.
  • A Takahashi, Y Watanuki, K Sato, A Kato, N Arai, J Nishikawa, Y Naito
    FUNCTIONAL ECOLOGY 17 (5) 590 - 597 0269-8463 2003/10 [Refereed][Not invited]
     
    1. Studying variability of parental foraging and provisioning behaviour in relation to reproductive success is fundamental to improving understanding of regulation of reproductive effort in animals. The hypothesis that parents with higher foraging effort have higher offspring growth rates was tested in chick-provisioning Adelie Penguins in Antarctica over five consecutive years. 2. Time spent diving per day, an index of foraging effort, varied among male and female parents, and among pairs. These daily interindividual or interpair differences in time spent diving appeared to be consistent over the 2-week study period within each breeding season. 3. Frequency of meals delivered by parents was positively correlated with their brood growth rate. Meal frequency was, however, independent of the amount of time spent diving per day by parents and the time spent diving did not affect brood growth rates. 4. Rates of body mass loss of breeding pairs were positively correlated with brood growth rates. 5. Our results did not support the hypothesis that parents with higher foraging effort have higher offspring growth rates. It is suggested that parental allocation of resources obtained during foraging, rather than the degree of foraging effort, is the more important process determining offspring growth rates in Adelie Penguins.
  • A Kato, Y Watanuki, Y Naito
    JOURNAL OF AVIAN BIOLOGY 34 (3) 282 - 287 0908-8857 2003/09 [Refereed][Not invited]
     
    Flight and diving activity of rhinoceros auklets Cerorhinca monocerata breeding on Teuri Island, Japan, were monitored during the summers 1999 and 2000 using miniaturized time-depth and acceleration recorders. Birds made 14.5 dive bouts per day of on average 15.4 min duration, which consisted of on average 16.2 dives of 12.1 m depth and 42.7 s duration. Birds made 13.8 +/- 7.3 flight bouts per day, which lasted on average 11.5 +/- 4.5 min. Daily total flight duration was 2.7 +/- 1.7 h (range 54 s-5.1 h) and the mean potential foraging range was estimated to be 87 km (maximum 164 km). Most birds stayed at the colony or rested on the water surface during the night. Rhinoceros auklets dived more actively in early morning and in late afternoon than during mid-day. Compared to results from studies of time allocation in other alcids species, rhinoceros auklets spent longer time flying (3.3 hd(-1)) and resting on water (13.1 hd(-1)), and less time diving (3.1 hd(-1)) and staying at the colony (4.4 hd(-1)). These foraging patterns are probably related to the nest attendance pattern of rhinoceros auklets, i.e. leaving the colony early in the morning, staying at sea all the day and returning to the colony in the evening to provision their chicks.
  • M Kuroki, A Kato, Y Watanuki, Y Niizuma, A Takahashi, Y Naito
    CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE 81 (7) 1249 - 1256 0008-4301 2003/07 [Refereed][Not invited]
     
    The diving behavior of Rhinoceros Auklets (Cerorhinca monocerata) breeding at Teuri Island, Hokkaido, Japan, was studied using small bird-borne time-depth dataloggers. The eight auklets made dives without an obvious horizontal bottom phase to a median depth of 14.0 +/- 1.8 (mean +/- SD) m (maximum 57 m) for 53 +/- 8 s (maximum 148 s) between the hours of 0300 and 2000. They made undulations (rapid depth changes), considered to represent prey pursuit, in 35% of the dives. Of the undulations, 57% occurred during the deep (>80% of maximum depth) parts of the dives and 26% during the ascent phase. The auklets performed 26 31 dives continuously during dive bouts of 32 34 min. Dive bouts at the end of the day were twice as long as in the morning and at midday. During dive bouts, the auklets showed consistent trends in dive depth, decreasing (23% of bouts), increasing (32%), or stable (19%), but sometimes they showed hectic depth changes (26%). V-shaped dives (with no horizontal bottom phase), potential prey pursuit in both the deep parts and ascent phases of the dives, and variable depth changes within dive bouts indicate the auklets' epipelagic feeding habits.
  • A Kato, Y Watanuki, Y Naito
    POLAR BIOLOGY 26 (6) 389 - 395 0722-4060 2003/06 [Refereed][Not invited]
     
    Foraging sites, diet, and diving behavior of chick-rearing Adelie penguins, Pygoscelis adeliae, in fast sea-ice areas were investigated during two consecutive seasons with contrasting sea-ice conditions. During 1995/1996, fast sea ice covered the foraging range of penguins during the whole breeding season. In contrast, during 1996/1997, sea ice covered the area in December 1996, but gradually thinned and finally broke up, so that open sea appeared along the coast during February 1997. Foraging sites were concentrated in a small area in 1995/1996 and spread over a wider area in 1996/1997 as more small open-water areas were available. In both seasons, parents traveled to more distant foraging sites as the season progressed and, consequently, the foraging-trip duration increased. In both years, Euphausia superba and Pagothenia borchgrevinki dominated the diet in the early part of the season, while later in the season penguins fed mainly on E. superba in 1995/1996 and Pagothenia borchgrevinki and E. crystallorophias in 1996/1997. In 1995/1996, penguins tended to dive deeper-albeit for a relatively shorter duration-when feeding mainly on krill compared to when feeding on fish. In 1996/1997, there was no difference in the dive depth and duration between krill- and fish-eating trips. Our results suggest that prey distribution changes annually and seasonally, probably according to sea-ice conditions, and that consequently penguins modify their foraging sites, diving patterns, and diet according to these changes.
  • Y Watanuki, Y Niizuma, GW Gabrielsen, K Sato, Y Naito
    PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 270 (1514) 483 - 488 0962-8452 2003/03 [Refereed][Not invited]
     
    In order to increase locomotor efficiency, breath-holding divers are expected to adjust their forward thrusts in relation to changes of buoyancy with depth. Wing propulsion during deep diving by Brunnich's guillemots (Uria lomvia) was measured in the wild by high-speed (32 Hz) sampling of surge (tail-to-head) and heave (ventral-to-dorsal) accelerations with bird-borne data loggers. At the start of descent, the birds produced frequent surges (3.2 Hz) during both the upstroke and the downstroke against buoyancy to attain a mean speed of 1.2-1.8 m s(-1) that was close to the expected optimal swim speed. As they descended deeper, the birds decreased the frequency of surges to 2.4 Hz, relaying only on the downstroke. During their ascent, they stopped stroking at 18 m depth, after which the swim speed increased to 2.3 m s(-1), possibly because of increasing buoyancy as air volumes expanded. This smooth change of surge frequency was achieved while maintaining a constant stroke duration (0.4-0.5 s), presumably allowing efficient muscle contraction.
  • Y Mori, A Takahashi, F Mehlum, Y Watanuki
    ANIMAL BEHAVIOUR 64 739 - 745 0003-3472 2002/11 [Refereed][Not invited]
     
    Although theoretical models predict that the quality of foraging patches has little effect on optimal dive time with increasing depth, many empirical studies show that dive time at a given depth may vary. We developed a model that incorporated patch quality as a parameter of energy intake as a nonlinear function of time, and applied it to the diving behaviour of Brunnich's guillemots, Uria lomvia. The model indicated that optimal dive time can vary widely depending on the parameter. It also explained the convergence of observed dive times with travel time. Assuming the birds dived optimally, this parameter can be estimated from travel time and dive time for each dive. Foraging patches with larger estimated parameter values were favoured by the birds, suggesting that the parameter indicated patch quality. We used this parameter to test an optimal patch use model in divers. The results indicate that Brunnich's guillemots adjust their diving behaviour adaptively depending on patch quality, and that the optimal diving model is valid for prediction of observed dive patterns if patch quality is incorporated appropriately. (C) 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.
  • Y Endo, H Asari, Y Watanuki, A Kato, M Kuroki, J Nishikawa
    POLAR BIOLOGY 25 (10) 730 - 738 0722-4060 2002/10 [Refereed][Not invited]
     
    We examined the biological characteristics of euphausiids found in the stomachs of Adelie penguins in relation to sea-ice conditions in Lutzow-Holm Bay over three seasons. Euphausiids, especially Euphausia superba, proved to be a staple food for Adelie penguins irrespective of the ice condition. Body length and maturity-stage compositions of euphausiids were different among seasons, probably reflecting sea-ice condition in summer. The mean body length decreased and maturity regressed during each season in E. superba, which was partly attributable to the selective feeding on large, mature female krill by Adelie penguins. The 1995/1996 year class of E. superba, which was spawned when the sea ice was most developed, was strong and conspicuous in the 1996/1997 and 1997/1998 seasons. This vigor indicates that sea ice provided females with good spawning conditions and larvae with good growth and survival rates.
  • Y Watanuki, A Kato, K Sato, Y Niizuma, CA Bost, Y Le Maho, Y Naito
    POLAR BIOLOGY 25 (9) 672 - 681 0722-4060 2002/09 [Refereed][Not invited]
     
    Adelie penguins (Pygoscelis adeliae) changed the pattern of energy allocation for self-maintenance and food provisioning among three colonies. Parents made longer trips (44-57 h) at Davis, where they foraged in open waters, than in Syowa (17-22 h) where fast sea-ice remained. Those at Dumont d'Urville, where the sea-ice disappeared in mid-summer, made trips of variable duration (22-41 h). During foraging trips, parents at Davis accumulated a greater amount of body tissue (0.40 kg) than parents at other locations (-0.06 to 0.13 kg) to offset the loss of body tissue during previous chick guarding. As a consequence, parents at these colonies had a similar body-mass decrease rate throughout the chick-rearing period (10-19 g/day). Parents with a smaller departure body mass seemed to make longer trips at Davis and Dumont d'Urville, and those making longer trips seemed to accumulate more body tissue at Davis, though these effects were not observed at Syowa. Stomach-content mass was greater at Davis (457 g) and Dumont d'Urville (551 g) than at Syowa (271-363 g), while the frequency of colony visits with meals was smaller at Davis (0.31/day per bird) and Dumont d'Urville (0.39/day per bird) than at Syowa (0.64-0.68/day per bird). Stomach-content mass was independent of trip duration. We propose the hypothesis that parents maintain their own body condition by regulating the accumulation of body tissue during foraging trips but change food provisioning with respect to variable foraging-trip duration.
  • Y Niizuma, Y Araki, H Mori, A Takahashi, Y Watanuki
    CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE 80 (9) 1549 - 1555 0008-4301 2002/09 [Refereed][Not invited]
     
    When rearing chicks, seabirds increase their daily energy expenditures during commuting flights between foraging areas and breeding colonies, owing to the heavy food loads. At this time, parents are expected to enlarge the size of their energy-supplying organs in response to the increased energy demands but reduce their total body mass to minimize the energetic cost of flight. The changes in body components of 40 incubating and chick-rearing rhinoceros auklets (Cerorhinca monocerata) were examined. Chick-rearing auklets did not have larger energy-supplying organs and breast muscles than incubating ones. However, chick-rearing auklets had greater ash composition, but smaller lipid contents, of breast muscles than incubating ones, whereas the former had a mass of water and protein similar to the latter. Male and female auklets lost a mean of 32.6 and 32.1 g in body mass between incubation and chick-rearing stages, mainly via loss of lipid reserves, which consequently reduces flight costs by 9.9 and 9.1%, respectively. Performance of commuting flight could be improved through changes in breast muscle compositions and reductions in total body mass. Although auklets did not enlarge their energy-supplying organs, their body conditions could be maintained within the same phase between the breeding stages.
  • Buoyancy and maximal diving depth in penguins: do they control inhaling air volume?
    K Sato, Y Naito, A Kato, Y Niizuma, Y Watanuki, JB Charrassin, CA Bost, Y Handrich, Y Le Maho
    JOURNAL OF EXPERIMENTAL BIOLOGY 205 (9) 1189 - 1197 0022-0949 2002/05 [Refereed][Not invited]
     
    Using a newly developed data logger to measure acceleration, we demonstrate that free-ranging king and Adelie penguins only beat their flippers substantially during the first part of descent or when they were presumed to be chasing prey at the bottom of dives. Flipper beating stopped during the latter part of ascent: at 29+/-9% (mean +/- S.D.) of dive depth (mean dive depth=136.8+/-145.1 m, N=425 dives) in king penguins, and at 52+/-20% of dive depth (mean dive depth=72.9+/-70.5 m, N=664 dives) in Adelie penguins. Propulsive swim speeds of both species were approximately 2ms(-1) during dives; however, a marked increase in speed, up to approximately 2.9ms(-1), sometimes occurred in king penguins during the passive ascending periods. During the prolonged ascending, oblique ascent angle and slowdown near the surface may represent one way to avoid the potential risk of decompression sickness. Biomechanical calculations for data from free-ranging king and Adelie penguins indicate that the air volume of the birds (respiratory system and plumage) can provide enough buoyancy for the passive ascent. When comparing the passive ascents for shallow and deep dives, there is a positive correlation between air volume and the depth of the dive. This suggests that penguins regulate their air volume to optimize the costs and benefits of buoyancy.
  • Osa Y, Watanuki Y
    J Yamashina Inst Ornithol 33 107 - 141 2002 [Refereed][Not invited]
  • K Ishikawa, Y Watanuki
    JOURNAL OF ETHOLOGY 20 (1) 49 - 54 0289-0771 2002 [Refereed][Not invited]
     
    Japanese cormorants, Phalacrocorax capillatus, are sexually dimorphic seabirds with males that are heavier and that dive deeper than females. Sex differences in prey composition and foraging behavior of those rearing chicks at Teuri Island, Hokkaido, were examined by collecting food-loads from parents in 1992-1998 and by radio-tracking ten birds each in 1997 and 1998 when prey availability was different. Males fed more on benthic and epibenthic fishes (82% mass) than did females (34%) while females fed more on epipelagic and coastal fishes (53%) than did males (18%). Males made longer dives (53 s) at feeding sites closer to the island (7 km) than females (39 s, 13 km) in 1997. In 1998 when the availability of epipelagic fish seemed to be higher, there were no sex differences in dive duration and distance to the feeding sites (35 s and 9 km for males, 36 s and 10 km for females). This sex difference in foraging behavior with a poor availability of epipelagic fish suggests that high diving ability possibly enables males to feed on demersal fish. Birds specializing in coastal shallow waters around the island made long divest hence they were probably foraging in bottom layers. Those foraging in deeper shelf waters made short dives and they were thought to forage in surface layers.
  • Watanuki Y
    J Yamashina Inst Ornithol 34 245 - 249 2002 [Refereed][Not invited]
  • A Kato, Y Watanuki, Y Naito
    ECOLOGICAL RESEARCH 16 (4) 745 - 758 0912-3814 2001/12 [Refereed][Not invited]
     
    Seabirds are high trophic predators in marine ecosystems and are sensitive to change in food supply and thus seabirds can be used as monitors of the marine environment. In order to study the foraging responses of Japanese cormorants Phalacrocorax filamentosus breeding at Teuri Island, Hokkaido to changes in fish availability, the diet was assessed from the regurgitations of parents and chicks, and diving behavior was measured by using time-depth recorders. Breeding performance (brood size, chick growth, breeding success) was monitored busing conventional methods to study their breeding responses. Japanese cormorants changed the diet and foraging behavior over four summers. The birds fed mainly on epipelagic schooling fish when they were available and on demersal fish when pelagic fish availability was low. They tended to dive deeper and longer in a year when they fed mainly on demersal fish than the other years, reflecting the change in the depth distribution of prey fish. Chick growth rate did riot differ among years, but fledging success was lower in the years of demersal fish as their meal delivery rate was low. When epipelagic schooling fish were considered scare, parents maintained chick growth by reducing brood size. High variability and unpredictability in pelagic fish abundance are key factors affecting the foraging and breeding performance of Japanese cormorants, which could potentially be used to monitor fish resources.
  • Diving behaviour and foraging habitats of Brunnich's guillemots (Uria lomvia) breeding in the High-Arctic
    F Mehlum, Y Watanuki, A Takahashi
    JOURNAL OF ZOOLOGY 255 413 - 423 0952-8369 2001/11 [Refereed][Not invited]
     
    The foraging behaviour of Brunnich's guillemots Uria lomvia was studied in a high-arctic fjord system (Kongsfjorden) in western Spitsbergen. The physical oceanographic characteristics of the water change from the head of the fjord and westward into the Greenland Sea, and are reflected in the vertical profiles of water temperatures in different parts of the area. Nine chick-rearing Brunnich's guillemots were instrumented with temperature-depth recorders, which generated vertical temperature profiles of the dives. These were compared to synoptic measurements of the water temperature characteristics of the region. This method was used to locate the foraging areas of the Brunnich's guillemots and to study the foraging site fidelity of individual birds. The results showed that only three of the nine birds foraged outside Kongsfjorden during the study period, and only 26 of the 186 dive bouts (14%) were conducted outside the fjord, 48-58 km from the colony. Most dives were probably made only a few kilometres from the colony. The data indicate that the birds showed strong fidelity to foraging areas at spatial scales of 1-20 km. However, the birds sometimes moved between feeding areas characterized by different vertical temperature profiles. The guillemots made 2229 dives during the study period and spent c. 10% of their time under water. The diving depth averaged 45 m, and the dive duration averaged 97 s. The deepest dive recorded was 136 m and lasted 196 s. We did not find any diel rhythm in the diving depths of the Brunnich's guillemots. Also, we found no diel pattern in diving frequency. These findings contradict the predominance of night-time diving observed in studies of guillemots undertaken further south.
  • A Takahashi, M Kuroki, Y Niizuma, A Kato, S Saitoh, Y Watanuki
    MARINE BIOLOGY 139 (2) 361 - 371 0025-3162 2001/08 [Refereed][Not invited]
     
    Temporal variation in the diet and chick growth of rhinoceros auklets (Cerorhinca monocerata), on Teuri Island., Sea of Japan, was studied to understand how local marine environmental changes affect the reproduction of this piscivorous seabird. The food delivered by parents to chicks was sampled every 1-2 weeks from late May to July, 1994-1998. Overall, the diet of nestling rhinoceros auklets consisted of (by mass) 61 % Japanese anchovy (Engraulis japonicus), 18% Japanese sand lance (Ammodytes personatus), 18% Japan Sea greenling (Pleurogrammus azonus), 2% other fish and 1% squid. Among years, the contribution of anchovy ranged from 16% to 93%. Once anchovy occurred in the diet, it dominated (80% on average) thereafter. Accordingly, when anchovy appeared in the diet early in the chick-rearing season (1994, 1998), the contribution of anchovy overall was large. The first appearance of anchovy in the diet of auklets late in the summer of 1997 was possibly related to negatively anomalous sea-surface temperature. Food loads composed of anchovy (34.0 g) were heavier than those of sand lance (22.5 g) and greenling (28.5 g). I The energy density of anchovies also was higher: 6.3 kJ g(-1) wet mass compared to 0+ greenling (4.78 kJ g(-1)) and 0+ sand lance (3.78 kJ g(-1)). Thus, a high proportion of anchovy in the diet resulted in high food load mass, high daily growth rates of chicks and high fledging success. This study highlighted the importance of the time of arrival of migratory high-lipid prey, which is influenced by local oceanographic conditions, to the reproductive performance of a piscivorous seabird.
  • Water temperature sampling by foraging Brunnich's Guillemots with bird-borne data loggers
    Y Watanuki, F Mehlum, A Takahashi
    JOURNAL OF AVIAN BIOLOGY 32 (2) 189 - 193 0908-8857 2001/06 [Refereed][Not invited]
     
    We describe the features of waters where seabirds were feeding by sampling vertical water temperature profiles with data loggers mounted on five Brunnich's Guillemots in Svalbard, Norway. The guillemots foraged in a cold water (-0.5-0.5 degreesC SST (sea surface temperature)) by making 1.8 dive bouts in short trips (32-257 min duration) as well as in moderate (0.5-2.0 degreesC SST) and warm waters (2.5-4.0 degreesC SST) by making 6.0 dive bouts during long trips (411-688 min duration). Judging from out bound flying time (15.7-24.4 min), time between dive bouts (23.9-43.3 min) and water types, the birds probably fed in fjord or coastal waters during short hips and in both coastal and offshore waters during long trips. Water temperature and diving behaviour can be simultaneously recorded by small data loggers, which therefore will provide useful information on marine features and foraging activity of top predators.
  • Y Niizuma, A Takahashi, N Sasaki, S Hayama, N Tokita, Y Watanuki
    ECOLOGICAL RESEARCH 16 (2) 197 - 203 0912-3814 2001/06 [Refereed][Not invited]
     
    When rearing chicks, Leach's storm-petrels (Oceanodroma leucorhoa) commute between foraging areas and breeding colonies with heavy food loads. At this time they should maximize the size of energy-supplying organs in response to increased energy expenditure but minimize total body mass to decrease the energetic cost of flight. Nineteen storm-petrels were killed to examine the changes in body composition and the masses of energy-supplying organs in birds that were incubating and rearing chicks. Parents lost a mean of 7.95 g in body mass between the stages of incubation and chick-rearing mainly via a loss of skin including subcutaneous adipose tissue, and a small fraction of heart and digestive organs, which are considered energy-supplying organs. This mass loss actually enables them to decrease flight cost by 14.4%. The benefits of decreasing flight costs by reducing total body mass are greater than if the energy-supplying organs of birds are enlarged only.
  • ナホトカ号油流失事故によって死亡したウトウの外部形態と栄養状態に関する報告。
    新妻靖章, 石川宏治, 森宏枝, 荒木葉子, 長雄一, 綿貫豊
    STRIX 19 81 - 89 2001 [Not refereed][Not invited]
  • Variation in foraging and parental behavior of King Cormorants
    A Kato, Y Watanuki, Nishiumi, I, M Kuroki, P Shaughnessy, Y Naito
    AUK 117 (3) 718 - 730 0004-8038 2000/07 [Refereed][Not invited]
     
    We Studied sexual and individual differences in foraging and parental behavior of King Cormorants (Phalacrocorax albiventer) during the brood-rearing period at Macquarie island. King Cormorants exhibit sexual dimorphism in size, with males being 16% heavier than females. Females foraged mainly in the morning and males in the afternoon. Five females were shallow divers (1.9 to 6.8 m), and seven females were deep divers (19.6 to 28.0 m); males dived deeper (15.6 to 44.2 m) than both groups of females. The amount of time spent on the bottom ("bottom time") relative to the dive cycle was higher for shallow-diving females ((x) over bar = 40 +/- SD of 13%) than for males ((x) over bar = 26 +/- 4%) and deep-diving females ((x) over bar = 27 +/- 3%). Total daily dive time and bottom time per day did not differ significantly among groups because shallow-diving females dived more often ((x) over bar = 211 +/- 81 dives per day) than males ((x) over bar = 68 +/- 21) and deep-diving females ((x) over bar = 70 +/- 7). Provisioning rate, trip duration, and proportion of time at sea did not differ significantly for males, deep-diving females, and shallow-diving females. Females, especially shallow divers, compensated for their shallow and short dives with more frequent dives. Consequently, male and female King Cormorants provisioned their chicks at similar rates despite large individual variation in foraging behavior.
  • Biological characteristics of euphausiids preyed upon by Adélie penguin, Pygoscelis adeliae, breeding at Hukuro Cove, Lützow-Holm Bay in 1995/1996.
    Endo Y, Asari H, Watanuki Y
    Polar Bioscience 13 66 - 73 2000 [Refereed][Not invited]
  • Parental food provisioning is unrelated to manipulated offspring food demand in a nocturnal single-provisioning alcid, the Rhinoceros Auklet
    A Takahashi, M Kuroki, Y Niizuma, Y Watanuki
    JOURNAL OF AVIAN BIOLOGY 30 (4) 486 - 490 0908-8857 1999/12 [Refereed][Not invited]
     
    The effects of offspring food demand on the regulation of parental food provisioning were examined in the Rhinoceros Anklet Cerorhincha monocerata, a nocturnal single-provisioning species, by conducting mate removal and supplementary feeding experiments, Parents did not adjust their level of food provisioning in response to an increased or a decreased chick food demand, contrasting with previous studies of the Atlandtic Puffin Fratercula arctica and procellariiforms that provision their chicks at shorter intervals. The chicks reared by a single parent grew more slowly while those receiving supplementary food grew faster and fledged heavier and younger, The body condition of parents did not change.
  • Body mass and dive duration in alcids and penguins
    Y Watanuki, AE Burger
    CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE 77 (11) 1838 - 1842 0008-4301 1999/11 [Refereed][Not invited]
     
    Interspecific allometric equations for dive duration were calculated for two groups of wing-propelled divers: penguins, which specializing in diving, and alcids, which balance demands for aerial flying with those of diving. The equations for maximum dive duration (min) were 1.433M(0.702) and 3.612M(0.735) (where M is body mass in kilograms) for penguins (10 species) and alcids (9 species), respectively, hence did not support a simple oxygen store/usage hypothesis based on the prediction that the mass exponent of aerobic dive limit is close to 0.25. Equations for feeding dives were 0.569M(0.712) and 1.094M(0.391) in penguins (9 species) and alcids (10 species), respectively. The allometric exponent for the duration of feeding dives for penguins did not match the predicted value of 0.25, but that for alcids did not differ significantly from this value. Alcids exhibited a maximum dive duration 2.5 times longer than that for penguins after mass effects were controlled for. The size of oxygen stores and metabolic rates based on laboratory studies of penguins and alcids failed to explain the longer dive duration in alcids than in penguins.
  • Y Nakayama, S Matsuoka, Y Watanuki
    ECOLOGICAL RESEARCH 14 (3) 291 - 301 0912-3814 1999/09 [Refereed][Not invited]
     
    Japanese monkeys, Macaca fuscata, living in a cool temperate forest experienced energy crises in winter. We measured feeding times and feeding rates (mass of foods eaten per unit time of feeding) in six different-sized, age-sex classes (1.2-12.6 kg body mass) in autumn and winter. One-, 2- and 3 similar to 4-year-olds spent 34-35%; and 44-46% of the day feeding in autumn and winter, respectively. Monkeys less than 0 years old spent less time feeding (16-28%) than average in winter and autumn; adult females spent less (41%) in winter; and adult males spent less (25%) in autumn. All age-sex classes ate mainly fruits in autumn and the heavier classes fed more on tree bark than buds in winter. The feeding rate for fruits (2.3-53.5 g min(-1)) was nine to 12 times faster than those for buds (1.0-4.8 g min(-1)) and bark (0.5-4.4 g min(-1)), and energy content did not differ among fruits (22.1 kJ g(-1) dry mass), buds (19.9 kJ g(-1) dry mass) and bark (23.2 kJ g(-1) dry mass). Energy base feeding rates increased with body mass where the body mass exponent for buds (0.29) was smaller than those for bark (0.64) and fruits (0.63), which might be attributable to the unit size of food items and mass dependency of masticatory apparatus. Our monkeys obtained two to five times more energy in autumn (1567-1150 kJ day(-1)) than in winter (604-3020 kJ day(-1)). Adult females obtained 60% of expected energy expenditure and other classes obtained 77-88% of that in winter.
  • A Kato, Y Watanuki, P Shaughnessy, Y Le Maho, Y Naito
    COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE III-SCIENCES DE LA VIE-LIFE SCIENCES 322 (7) 557 - 562 0764-4469 1999/07 [Refereed][Not invited]
     
    Cormorants feed by feet-propelled diving, How cormorants optimize foraging is of a particular interest in relation to the understanding of the feeding strategies of diving birds, as well as within the debate about cormorants' impact on sustainable resources. Using microdata loggers that recorded diving depth, we investigated the foraging strategy of males and females of subantarctic cormorants, which inhabit cold regions, and of Japanese cormorants, which live in the northern temperate zone. For both species, males and females daily spent the same amount of time submerged, and apparently captured the same amount of fish. However, males dived deeper and longer, which could be explained by their 15-20 % larger body mass and may minimize potential competition for food. (C) Academie des Sciences / Elsevier, Paris.
  • A Takahashi, Y Niizuma, Y Watanuki
    ECOLOGICAL RESEARCH 14 (2) 155 - 164 0912-3814 1999/06 [Refereed][Not invited]
     
    We examined the effects of offspring food demand on parental regulation of food provisioning and body condition in a small long-lived seabird, Leach's storm-petrels (Oceanodroma leucorhoa). In one experimental group, food demand of chicks on their parents was increased by removing one parent ('single'), and in another group these food demands were decreased by supplementary feeding of chicks ('supplement'). A further unmanipulated group provided a 'control'. Feeding frequencies by one parent were higher in the single but lower in the supplement than in the control group, in accordance with the food demand of chicks. The size of meals appeared to be not different among the experimental groups. However, as single parents did not compensate perfectly for the increase of chick food demand by food provisioning, single chicks grew at slower rates and fledged at smaller masses than control chicks. Supplement chicks grew at similar rates and fledged at similar masses as control chicks, because parents decreased food provisioning and food processing capacity of the chicks might be limited. The body condition of parents, which was determined by body mass loss and feather regrowth rate, did not differ among the groups. These results indicate that feeding frequency was regulated by parental decision in this storm-petrel species. Parents may adjust their food provisioning to match the food demand of chicks but within a certain range so as not to deteriorate their own body condition.
  • Energy expenditure of incubating Leach's Storm-petrels in artificial nest boxes in the wild.
    Niizuma Y, Takahashi, A, Watanuki, Y
    Jpn J Ornithol 47 49 - 53 1999 [Refereed][Not invited]
  • Dive bouts and feeding sites of Adelie Penguins rearing chicks in an area with fast sea-ice
    Y Watanuki, Y Miyamoto, A Kato
    WATERBIRDS 22 (1) 120 - 129 0738-6028 1999 [Refereed][Not invited]
     
    Diving behavior and feeding sites of 22 Adelie Penguins (Pygoscelis adeliae) foraging at small open-water leads were simultaneously measured by bird-borne small data-loggers and land-based radio tracking in an area covered with fast sea-ice. The Adelies foraged in ice cracks along the share in early and mid January and around icebergs in late January. We identified a minimum of 1.6-3.7 feeding sites per foraging trip, executing 3.2-6.2 dice bouts of 78-85 min. duration at feeding sites. Birds changed feeding sites during 9.6% of the inter-bout intervals but staved within a site for 80.7% of the intervals. Duration of inter-bout intervals did not differ between birds changing feeding sites and those staying. Surface time to dice duration ratio increased with the dive sequence for dive bouts before leaving feeding sites, though this effect was not significant for those staying. Large variation in dice depth occurred within dive bouts, while dive bouts, feeding sites and sea depth had no strong effects on dice depth, indicating that penguins foraged at variable depth in mid and surface waters under the ice.
  • 抱卵コストはオオセグロカモメのクラッチサイズを制約するか?
    高橋康朗, 新妻靖章, 帖地美千代, 石川宏治, 綿貫豊
    日本鳥学会誌 48 127 - 133 1999 [Refereed][Not invited]
  • 岡奈理子, 高橋晃周, 石川宏治, 綿貫豊
    山階鳥研報 31 108 - 133 1999 [Not refereed][Not invited]
  • Sexing by external measurements of adult Rhinoceros Auklets breeding on Teuri Island.
    Niizuma Y, Takahashi A, Kuroki M, Watanuki Y
    Japanese Journal of Ornithology 48, 145-150.  1999 [Refereed][Not invited]
  • Niizuma Y, Takahashi A, Sawada M, Watanuki Y
    J Yamashina Inst Ornithol 30 361 - 39 1998 [Refereed][Not invited]
  • Kato A, Watanuki Y, Naito Y
    J Yamashina Inst Ornithol 30 101 - 108 1998 [Refereed][Not invited]
  • 黒木麻希, 加藤明子, 綿貫豊, 高橋晃周
    山階鳥研報 30 40 - 46 1998 [Refereed][Not invited]
  • Diving and foraging behaviour of Adelie penguins in areas with and without fast sea ice
    Y Watanuki, A Kato, Y Naito, G Robertson, S Robinson
    POLAR BIOLOGY 17 (4) 296 - 304 0722-4060 1997/04 [Refereed][Not invited]
     
    The diving and foraging behaviours of Adelie penguins, Pygoscelis adeliae, rearing chicks at Hukuro Cove. Lutzow-Holm Bay, where the fast sea-ice remained throughout summer, were compared to those of penguins at Magnetic Island, Prydz Bay, where the fast sea-ice disappeared in early January. Parent penguins at Hukuro Cove made shallower (7.1-11.3 m) but longer (90-111 s) dives than those at Magnetic Island (22.9 m and 62 s). Dive duration correlated with dive depth at both colonies (r(2) = 0.01 similar to 0.90), but the penguins at Hukuro Cove made longer dives for a given depth. Parents at Hukuro Cove made shorter foraging trips (8.1-14.4 h) with proportionally longer walking/swimming (diving <1 m) travel time (27-40% of trip duration) and returned with smaller meals (253-293 g) than those at Magnetic Island, which foraged on average for 57.2 h, spent 2% of time walking/swimming <1 m) travel, and with meals averaging 525 g. Trip duration at both colonies correlated to the total time spent diving. Trip duration at Hukuro Covet but not at Magnetic Island, increased as walking/swimming <1 m) travel time increased. These differences in foraging behaviour between colonies probably reflected differences in sea-ice cover and the availability of foraging sites.
  • NiizumaY, Watanuki Y
    J Yamashina Inst Ornithol 29 83 - 90 1997 [Refereed][Not invited]
  • Diving pattern and stomach temperatures of foraging king cormorants at subantarctic Macquarie Island
    A Kato, Y Naito, Y Watanuki, PD Shaughnessy
    CONDOR 98 (4) 844 - 848 0010-5422 1996/11 [Refereed][Not invited]
  • Diving performance of male and female Japanese cormorants
    Y Watanuki, A Kato, Y Naito
    CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE 74 (6) 1098 - 1109 0008-4301 1996/06 [Refereed][Not invited]
     
    Sexual differences in the diving behavior of the sexually dimorphic Japanese Cormorant, Phalacrocorax capillatus (males are 26% heavier than females), were studied at Teuri Island, Hokkaido, using time-depth recorders. A typical dive cycle involved a rapid descent phase, a bottom phase where they remained for a while, an ascent phase, and a postdive surface phase. Depth and duration across individual birds were greater for males (15.1 +/- 3.7 (mean +/- SD) m, 37 +/- 5 s, respectively) than those for females (7.2 +/- 2.4 m, 24 +/- 4 s, respectively). While submerged, females spent a similar proportion of time during the bottom phase to males, hence foraging efficiency (proportion of time at the bottom to total dive cycle time) did not differ between the sexes. No sexual differences were found in descent and ascent rates, dive bout duration, or time spent underwater per day. No significant effects of dive duration on postdive surface time were observed for either sex, indicating that birds dived within an aerobic dive limit. However, mean dive durations and maximum dive durations for individual birds were a function of body mass to the power 1.49 and 1.87, respectively, suggesting that body mass partly constrains the diving behavior of this opportunistically feeding cormorant.
  • Comparison of trace element concentrations in tissues of the chick and adult Adélie penguins.
    Yamamoto Y, Kanesaki S, Kuramochi T, Miyazaki N, Watanuki Y, Naito Y
    Proceedings of NIPR Symp Polar Biol 0 253 - 262 1996 [Refereed][Not invited]
  • EUPHAUSIA-SUPERBA DOMINATES IN THE DIET OF ADELIE PENGUINS FEEDING UNDER FAST SEA-ICE IN THE SHELF AREAS OF ENDERBY-LAND IN SUMMER
    Y WATANUKI, Y MORI, Y NAITO
    POLAR BIOLOGY 14 (6) 429 - 432 0722-4060 1994/08 [Refereed][Not invited]
     
    Adelie penguins Pygoscelis adeliae in Enderby Land, Antarctica feed mainly on Euphausia superba during the chick rearing season in shelf areas where fast sea-ice remains: indicating that E. superba is abundant under the fast sea-ice in these areas. The shelf areas in Enderby Land, therefore, are unique since the previous studies of Adelie penguin diet in Ross Sea, Adelie Land and Prydz Bay show that E. crystallorophias is the most abundant krill species in shelf areas in general.
  • Watanuki Y, Kato A, Robertson G
    J Yamashina Inst Ornithol 26 109 - 114 1994 [Refereed][Not invited]
  • Y WATANUKI, Y NAKAYAMA, S AZUMA, S ASHIZAWA
    PRIMATES 35 (1) 15 - 24 0032-8332 1994/01 [Refereed][Not invited]
     
    The Japanese monkey (Macaca fuscata) winter range utilization and the effects of foraging on mulberry trees (Morus bombycis) were studied in the Shimokita Peninsula during four winter seasons. The monkeys ate mainly winter dormancy buds when they visited the mulberry tree clumps for the first time within the winter, but they ate mainly bark when they visited for the second or third times. In the areas utilized by the monkeys over the recent three years, the mulberry trees compensated for the decrease in their number of shoots by producing longer shoots with more buds against the monkey foraging. In the areas used every year for more than four years, however, the mulberry trees were unable to compensate for the foraging pressure. Thus, although the monkeys had apparently operated prudent herbivory within three years, they did not do so on a longer time-scale. They shifted their utilization ranges after having over-exploited the mulberry trees.
  • Y WATANUKI, Y NAKAYAMA
    PRIMATES 34 (4) 419 - 430 0032-8332 1993/10 [Refereed][Not invited]
     
    Air temperature, snow depth, and diet composition were found to affect the activity budgets of 1 similar to 2-year-old, 3 similar to 4-year-old and adult female (> 5 years old) Japanese monkeys (Macaca fuscata) in the Shimokita Peninsula. They spent more time resting as the air temperature decreased. They spent less time moving on the ground, so that they moved shorter distances, where the snow was deep. However, they spent more time moving on the ground as they fed more on fruits and seeds. Adult females moved mainly on the ground, while 1 similar to 2-year-olds moved on the tree branches as well as on the ground. Adult females increased their time moving on the tree branches where the snow was deep but 1 similar to 2- and 3 similar to 4-year-olds did not. The 1 similar to 2- and 3 similar to 4-year-olds but not adult females increased their feeding time as they fed more on buds and barks containing abundant fiber. We hypothesize that the large body size of adult females may constrain them to move mainly on the ground, and might enable them to choose energy saving tactics more easily.
  • APPLICATION OF COMPUTED-TOMOGRAPHY TO MORPHOLOGICAL-STUDY OF EMPEROR AND ADELIE PENGUINS
    Y OSA, T KURAMOCHI, Y WATANUKI, Y NAITO, M MURANO, SI HAYAMA, H ORIMA, M FUJITA
    AUK 110 (3) 651 - 653 0004-8038 1993/07 [Refereed][Not invited]
  • DIVING PATTERN AND PERFORMANCE IN THE MACARONI PENGUIN EUDYPTES-CHRYSOLOPHUS
    JP CROXALL, DR BRIGGS, A KATO, Y NAITO, Y WATANUKI, TD WILLIAMS
    JOURNAL OF ZOOLOGY 230 31 - 47 0952-8369 1993/05 [Refereed][Not invited]
     
    The pattern and characteristics of diving in two female macaroni penguins Eudyptes chrysolophus was studied, during the brooding period, using continuous-recording time-depth recorders, for a total of 18 days (15 consecutive days) during which the depth, duration and timing of 4876 dives were recorded. Diving in the first 11 days was exclusively diurnal, averaging 244 dives on trips lasting 12 hours. Near the end of the brooding period trips were longer and included diving at night. About half of all trips (except those involving continuous night-time diving) was spent in diving and dive rate averaged 14-25 dives per hour (42 per hour at night). The duration of daytime dives varied between trips, and averaged 1.4-1.7 min, with a subsequent surface interval of 0.5-0.9 min. Dive duration was significantly directly related to depth, the latter accounting for 53% of the variation. The average depths of daytime dives were 20-35 m (maximum depth 115 m). Dives at night were shorter (average duration 0.9 min) and much shallower (maximum 11 m); depth accounted for only 6% of the variation in duration. Estimates of potential prey capture rates (3-5 krill per dive; one krill every 17-20 s) are made. Daily weight changes in chicks were directly related to number of dives, but not to foraging trip duration nor time spent diving. Of the other species at the same site which live by diving to catch krill, gentoo penguins forage exclusively diurnally, making longer, deeper dives; Antarctic fur seals, which dive to similar depths as macaroni penguins, do so mainly at night.
  • Mortality of eggs and nest attendance pattern in Adélie Penguins in Lutzow-Holm Bay.
    Watanuki Y
    Jpn J Ornithol 42 1 - 8 1993 [Refereed][Not invited]
  • DIVING PERFORMANCE OF ADELIE PENGUINS IN RELATION TO FOOD AVAILABILITY IN FAST SEA-ICE AREAS - COMPARISON BETWEEN YEARS
    Y WATANUKI, A KATO, Y MORI, Y NAITO
    JOURNAL OF ANIMAL ECOLOGY 62 (4) 634 - 646 0021-8790 1993 [Refereed][Not invited]
     
    1. Between-year variation in adelie penguin Pygoscelis adeliae foraging behaviour was studied using time-depth recorders at a colony in Lutzow-Holm Bay, Antarctica in the summers of 1990 and 1991 in areas where fast sea-ice remained. Poor chick survival and growth, long foraging trip duration and low meal delivery rate indicate that food availability was poor in 1991 when compared to 1990. However, mass of food brought to chicks per shore visit and rate of decrease of parental mass did not differ between these years. 2. In 1991, the penguins on average dived deeper (12.3 +/- 4.2 m) and for longer durations (1.9 +/- 0.2 min) than they did in 1990 (7.1 +/- 1.6 m depth and 1.5 +/- 0.2 min duration). However, time under water, the number of dive bouts per day and dive bout duration did not differ significantly between 1990 and 1991. 3. Foraging trip duration of birds carrying the time-depth recorders in mid to late January was longer in 1991 (861 +/- 419 min) than in 1990 (502 +/- 199 min) because travelling/searching time within trips in 1991 was about four times as long as it had been in 1990. Total dive bout duration within foraging trips did not differ between 1990 and 1991. These indicate that probability of locating a prey patch was lower in 1991 than in 1990, but once a prey patch was found total diving effort was similar to that in 1990. 4. These data show that when food was less abundant adelie penguin parents increased the duration of their foraging trips, thereby decreasing meal delivery rate, but did not increase total diving effort to compensate for poor food availability. The reasons for this might be that (i) their foraging sites were highly restricted to small ice holes or tide cracks; therefore, prey abundance within sites might decrease rapidly by depletion and the penguins might not be able to get more food even if they forage for a longer period; or (ii) they have a priority to maintain their body condition for their own future survival at the expense of offspring production.
  • ADELIE PENGUIN PARENTAL ACTIVITIES AND REPRODUCTION - EFFECTS OF DEVICE SIZE AND TIMING OF ITS ATTACHMENT DURING CHICK REARING PERIOD
    Y WATANUKI, Y MORI, Y NAITO
    POLAR BIOLOGY 12 (5) 539 - 544 0722-4060 1992/10 [Refereed][Not invited]
     
    Effects of device attachment on parental activities and body mass change in instrumented birds and their mates, and on chick growth and survival, were studied in Adelie Penguins Pygoscelis adeliae in Lutzow-Holm Bay, Antarctica. Penguins on which small devices were fitted with rubber band harnesses exhibited increased foraging trip duration, and decreased body mass, food delivery rate, chick growth and chick survival. Their mates did not increase food delivery rate. Those on which small or large devices were fitted with epoxy glue did not change foraging trip duration, body mass, or chick survival. However, large devices decreased chick growth. These effects were more obvious among penguins fitted with devices later in the chick rearing period, and suggest that: 1) parents fitted with devices give a priority to maintenance of their own energy reserve over guarding and food delivery for chicks; and, 2) parents' decreasing energy reserves later in the breeding season might intensify the effects of devices.
  • INDIVIDUAL DIET DIFFERENCE, PARENTAL CARE AND REPRODUCTIVE SUCCESS IN SLATY-BACKED GULLS
    Y WATANUKI
    CONDOR 94 (1) 159 - 171 0010-5422 1992/02 [Refereed][Not invited]
     
    In Slaty-backed Gulls, Larus schistisagus, some males prey on seabird chicks and deliver these prey to their own broods. Females rarely prey on seabird chicks. Effects of this individual diet variation on reproductive success in relation to parental care behavior were studied on Teuri Island, Hokkaido. Pairs delivering more seabird chicks to their broods raised more fledglings. Their chicks grew faster than those of pairs delivering mostly fish, possibly because energy value of food-loads with seabird chicks was greater than those with fish or marine invertebrates. Timing of breeding, territory size and egg volume also affected reproductive success. The diet variation was not, however, related to these factors. Diet overlap between mates did not affect division of parental care between mates nor reproductive success directly. Males tending to prey on seabird chicks remained more on territory, probably because their food was easily accessible and they foraged more efficiently. This may explain why their mates attended less than other females without decreasing reproductive success.
  • Chick diet and daily activity pattern of Common Murres and Black-legged Kittiwakes at Bluff seabirds colony, Norton Sound, Alaska.
    Watanuki Y, Naito Y, Schauer J
    Proceedings of NIPR Symp. Polar Biol. 5 98 - 104 1992 [Refereed][Not invited]
  • iving pattern and performance in male and female Blue-eyed Shags Phalacrocorax atriceps at South Georgia.
    Kato A, Croxall JP, Watanuki Y, Naito Y
    Marine Ornithology 19 117 - 129 1991 [Refereed][Not invited]
  • DAILY ACTIVITY PATTERN OF RHINOCEROS AUKLETS AND KLEPTOPARASITISM BY BLACK-TAILED GULLS
    Y WATANUKI
    ORNIS SCANDINAVICA 21 (1) 28 - 36 0030-5693 1990/03 [Refereed][Not invited]
  • Sex and individual variations in the diet of Slaty-backed Gulls breeding on Teuri island, Hokkaido.
    Watanuki Y
    Jpn J Ornithol 38 1 - 13 1989 [Refereed][Not invited]
  • INTRASPECIFIC PREDATION AND CHICK SURVIVAL - COMPARISON AMONG COLONIES OF SLATY-BACKED GULLS
    Y WATANUKI
    OIKOS 53 (2) 194 - 202 0030-1299 1988/09 [Refereed][Not invited]
  • 北海道周辺における海鳥繁殖地の現状
    綿貫豊, 近藤憲久, 中川元
    鳥 37 17 - 32 1988 [Refereed][Not invited]
  • Breeding biology and foods of Rhinoceros Auklets on Teuri Island, Japan.
    Watanuki Y
    Proc. NIPR Symp Polar Biol 1 175 - 183 1987 [Refereed][Not invited]
  • Watanuki, Y. 1987. Regional difference in the diet of Slaty-backed Gulls breeding around Hokkaido. Journal of Yamashina Institute for Ornithology, 20:71-81.*
    1987 [Not refereed][Not invited]
  • 天売島における海鳥の繁殖状況
    綿貫豊, 青塚松寿, 寺沢孝毅
    鳥 34 146 - 150 1986 [Refereed][Not invited]
  • MOONLIGHT AVOIDANCE-BEHAVIOR IN LEACH STORM-PETRELS AS A DEFENSE AGAINST SLATY-BACKED GULLS
    Y WATANUKI
    AUK 103 (1) 14 - 22 0004-8038 1986/01 [Refereed][Not invited]
  • FOOD OF BREEDING LEACHS STORM-PETRELS (OCEANODROMA-LEUCORHOA)
    Y WATANUKI
    AUK 102 (4) 884 - 886 0004-8038 1985 [Refereed][Not invited]
  • 大黒島におけるコシジロウミツバメ Oceanodroma leucorhoa の繁殖生態
    綿貫豊
    山階鳥類研究所研究報告 17 9 - 22 1985 [Refereed][Not invited]
  • Food intake and pellet of Black-tailed Gulls Larus crassirostris.
    Watanuki Y
    J Yamashina Inst Ornithol 16 168 - 169 1984 [Refereed][Not invited]
  • Predation and anti-predation behavior in seabirds on Teuri Island, Hokkaido.
    Watanuki Y
    J Yamashina Inst Ornithol 15 167 - 174 1983 [Refereed][Not invited]
  • Size selective hunting by Slaty-backed Gulls Larus schistisagus and influence on fledging success of Black-tailed Gulls L. crassirostris.
    Watanuki Y
    J Yamashina Inst Ornithol 15 167 - 174 1982 [Refereed][Not invited]

Books etc

  • 汚染物質の源を求めて海鳥をトラッキングする バイオロギング2 日本バイオロギング研究会編 動物たちの知られざる世界を探る
    綿貫 豊 (Joint work97-100)
    京都通信社 2016
  • 海鳥のモニタリング法 生態学フィールド調査法シリーズ 占部城太郎・日浦 勉・辻 和希(編)
    綿貫豊, 高橋晃周 (Joint work全て(1-136))
    共立出版 2016
  • ペンギンはなぜ飛ばないのか?海を選んだ鳥たちの姿
    綿貫 豊 (Single work)
    恒星社厚生閣 2013
  • 海鳥の行動と生態:その海洋生活への適応
    綿貫豊 (Single work)
    生物研究社 2010
  • 鳥との共存を目指して(日本鳥類保護連盟編)
    綿貫豊 (Contributor3章 3節 漁業)
    中央法規 2010
  • 動物たちの不思議に迫るバイオロギング(日本バイオロギング研究会編)
    綿貫豊 (Contributor潜水能力の秘密は「はばたき調節」)
    京都通信社 2009
  • 地球と生命の進化学:新・自然史科学I(沢田健・綿貫豊・西弘嗣・栃内新・馬渡俊輔(編著))
    綿貫豊 (Joint editorジュラ紀=白亜紀温室世界とその終焉—恐竜から鳥類へ)
    北海道大学図書出版会 2008
  • これからの鳥類学 山岸哲、樋口広芳(編)
    綿貫 豊 (Contributorオオセグロカモメはなぜ3卵しか産まないのか:生活史戦略研究の生理的基盤)
    裳華房 2002
  • The Status, Ecology, and Conservation of Marine Birds of the North Pacific In: K Vermeer, KT Briggs, KH Morgan, D. Siegel-Causey (eds),
    Vermeer K, Irons DB, Velarde E, Watanuki Y (ContributorStatus, conservation, and management of nesting Larus gulls in the North Pacific.)
    Canadian Wildlife Service Special Publication, Ottawa. 1993
  • 生態学からみた北海道 東正剛、阿部永、辻井達一(編)
    綿貫 豊 (Contributorコシジロウミツバメはなぜ月明りをさけるのか)
    北大図書刊行会 1993
  • 鳥類の繁殖戦略 (下)山岸哲(編)
    綿貫豊 (Contributor海鳥における捕食被食者相互関係)
    東海大学出版 1986

Works

  • 小笠原におけるクロアシアホウドリ採食行動
    2008
  • アラスカプリビロフ島におけるハシブトウミガラスの採食行動の研究
    2004 -2007
  • スコットランドメイ島における潜水性海鳥の潜水中の推進に関する研究
    2003 -2006
  • ルイパスツール大1ヶ月客員教授
    2004
  • オオミズナギドリの採食繁殖生態
    2002
  • スピッツベルゲン島におけるハシブトウミガラスの潜水生理生態に関する研究
    1998 -2001
  • 海氷とペンギンの採食生態繁殖生態に関する研究:日本南極地域観測隊40次夏隊
    1999 -2000
  • 海氷とペンギンの採食生態繁殖生態に関する研究:日本南極地域観測隊36次夏隊
    1995 -1996
  • 海氷とペンギンの採食生態繁殖生態に関する研究:オーストラリア南極観測隊92/93
    1992 -1993
  • 海氷とペンギンの採食生態繁殖生態に関する研究:日本南極地域観測隊31次越冬隊
    1989 -1990
  • 海氷とペンギンの採食生態繁殖生態に関する研究:日本南極地域観測隊30次夏隊
    1988 -1989
  • アラスカ州ノームにおけるウミガラス、ミツユビカモメの研究
    1988
  • 天売島における海鳥の採食生態と繁殖成績に関する研究
    1980

MISC

  • 田中厚資, 綿貫豊, 高田秀重, 石塚真由美, 山下麗, 水川薫子, 水川葉月, 池中良徳, 中山翔太  環境化学討論会要旨集(CD-ROM)  28th-  ROMBUNNO.P‐031  2019/06/11  [Not refereed][Not invited]
  • 太田能之, 久木田結愛, 長谷川悦子, 白石純一, 風間麻未, 風間健太郎, 綿貫豊  日本鳥学会大会講演要旨集  2018-  95  2018/09/14  [Not refereed][Not invited]
  • 庄子晶子, ELLIOTT K, ARIS‐BROSOU S, 水川葉月, 中山翔太, 池中良徳, 石塚真由美, 桑江朝比呂, 渡辺謙太, 綿貫豊  日本鳥学会大会講演要旨集  2018-  97  2018/09/14  [Not refereed][Not invited]
  • 風間健太郎, 先崎啓究, 安武与樹クロス, 馬鋭, 橋本詩津久, 先崎愛子, 風間麻未, 西沢文吾, 綿貫豊  日本鳥学会大会講演要旨集  2018-  93  2018/09/14  [Not refereed][Not invited]
  • 西沢文吾, THIEBOT Jean‐Baptiste, 富田直樹, 佐藤文男, 依田憲, 綿貫豊  日本鳥学会大会講演要旨集  2018-  57  2018/09/14  [Not refereed][Not invited]
  • アホウドリ保全の新たな展開
    綿貫 豊  生物の科学:遺伝  72-  165  -170  2018  [Not refereed][Invited]
  • 風間健太郎, 西沢文吾, 塚本祥太, JORDI Gonzalez E, 風間麻未, 綿貫豊  日本生態学会大会講演要旨(Web)  65th-  ROMBUNNO.P2‐224 (WEB ONLY)  2018  [Not refereed][Not invited]
  • 庄子晶子, ELLIOTT K, ARIS‐BROSOU S, 水川葉月, 中山翔太, 池中良徳, 石塚真由美, 桑江朝比呂, 渡辺謙太, 綿貫豊  日本鳥学会大会講演要旨集  2017-  70  2017/09/15  [Not refereed][Not invited]
  • 風間健太郎, 西沢文吾, 塚本祥太, GONZALEZ Jordi E, 風間麻未, 綿貫豊  日本鳥学会大会講演要旨集  2017-  71  2017/09/15  [Not refereed][Not invited]
  • 佐藤文男, 富田直樹, THIEBOT Jean‐Baptiste, 西沢文吾, 江田真毅, 泉洋江, 綿貫豊  日本鳥学会大会講演要旨集  2017-  65  2017/09/15  [Not refereed][Not invited]
  • 海洋汚染の生体影響を海鳥で測る
    綿貫 豊  エブオブ  66-  2  -5  2017  [Not refereed][Invited]
  • 新屋惣, 池中良徳, 中山翔太, 石井千尋, 水川葉月, 伊藤真輝, 高江洲昇, 大澤夏生, 綿貫豊, 石塚真由美  日本野生動物医学会大会・講演要旨集  23rd-  125  2017  [Not refereed][Not invited]
  • 海鳥をつかった海洋プラスチックのモニタリングと生体影響評価
    綿貫 豊  月刊海洋  49-  654  -661  2017  [Not refereed][Not invited]
  • Spatial ecology of marine top predators in the North Pacific: Tools for integrating across data sets and identifying high use areas.
    WATANUKI Yutaka  PICES Sci Rep  (50)  1  -55  2017  [Not refereed][Not invited]
  • 塚本祥太, 西沢文吾, 佐藤文男, 富田直樹, 綿貫豊  日本鳥学会大会講演要旨集  2016-  92  2016/09/16  [Not refereed][Not invited]
  • 三瓶真, 西沢文吾, 和賀久朋, 阿部義之, 藤原周, 綿貫豊, 西野茂人, 平譯享  極域科学シンポジウム(Web)  7th-  IA_Sampei_00258_01 (WEB ONLY)  2016  [Not refereed][Not invited]
  • 海鳥にとっての津軽海峡:オオミズナギドリの分布
    綿貫豊, 西沢文吾  水産海洋研究  80-  247  -248  2016  [Not refereed][Not invited]
  • オオミズナギドリをつかった海洋汚染モニタリング
    山下麗, 高田秀重, 綿貫豊  月刊海洋  48-  439  -447  2016  [Not refereed][Not invited]
  • ウミスズメ科の多様性
    綿貫 豊  Strix  32-  3  -16  2016  [Not refereed][Not invited]
  • 生態系における汚染
    綿貫豊, 関島恒夫  生態学会誌  66-  31  -35  2016  [Not refereed][Not invited]
  • 綿貫豊, 山下愛, 石塚真由美, 池中良徳, 中山翔太, 石井千尋, 山本誉士, 山本誉士, 伊藤元裕, 桑江朝比呂, 鈴木裕也, 新妻靖彰, MEATHREL C.E, TRATHAN P.N, PHILLIPS R.A  環境化学討論会要旨集(CD-ROM)  24th-  ROMBUNNO.P‐146  2015/06/17  [Not refereed][Not invited]
  • 綿貫 豊, 西沢 文吾, 伊藤 元裕  モーリー : 北海道ネーチャーマガジン : Hokkaido nature magazine mally  (39)  図巻頭1p,1  -4  2015/06  [Not refereed][Not invited]
  • 佐々木裕子, 松野孝平, 大額実咲, 上野洋路, 和賀久朋, 山口篤, 平譯享, 綿貫豊  日本海洋学会大会講演要旨集  2015-  124  2015/03  [Not refereed][Not invited]
  • 天売島のウトウの餌と繁殖成績の変化から見た日本海:2014年の激変
    綿貫 豊  水産海洋研究  79-  333  -351  2015  [Not refereed][Invited]
  • 岩原由佳, 関口圭子, 松野孝平, 中野翼, 西沢文吾, 鵜山貴司, 山口篤, 綿貫豊, 宮下和士, 三谷曜子  日本水産学会大会講演要旨集  2014-  107  2014/03/27  [Not refereed][Not invited]
  • 佐々木裕子, 松野孝平, 和賀久朋, 大額実咲, 山口篤, 上野洋路, 平譯享, 綿貫豊  極域科学シンポジウム講演予稿集(CD-ROM)  5th-  ROMBUNNO.IAP45  2014  [Not refereed][Not invited]
  • 海鳥によるプラスチックの飲み込みとその影響
    綿貫 豊  海洋と生物  215-  596  -605  2014  [Not refereed][Not invited]
  • チャクチ海、底性生物の変化:おしょろ丸トロール調査から見えてきたこと
    中野翼, 綿貫豊  北極通信  04-  4  -4  2014  [Not refereed][Not invited]
  • 綿貫豊, 山下愛, 保科賢司, 鈴木優也, 山本誉士, 石塚真由美, 池中良徳, 中山翔太, 石井千尋, 新妻靖章, MEATHREL C, PHILLIPS R. A  日本鳥学会大会講演要旨集  2013-  53  2013/09/13  [Not refereed][Not invited]
  • 石井千尋, 池中良徳, 中山翔太, 鈴木優也, 綿貫豊, 渡邊雄児, 福若雅章, YOHANNES Yared B, 川合佑典, 石塚真由美  環境化学討論会要旨集(CD-ROM)  22nd-  ROMBUNNO.1-1B-1-1  2013/07  [Not refereed][Not invited]
  • 綿貫豊, 山下愛, 石塚真由美, 池中良徳, 中山翔太, 石井千尋, 山本誉士, 伊藤元裕, 桑江朝比呂  日本生態学会大会講演要旨集  60th-  118  2013/03/05  [Not refereed][Not invited]
  • 石井千尋, 池中良徳, 中山翔太, 鈴木優也, 綿貫豊, 渡邊雄児, 福若雅章, YARED Yohannes Beyene, 川合佑典, 石塚真由美  日本獣医学会学術集会講演要旨集  155th-  260  2013/03/04  [Not refereed][Not invited]
  • 山本誉士, 保科賢治, 西沢文吾, MEATHREL Catherine, PHILLIPS Richard, 綿貫豊  極域科学シンポジウム講演予稿集(CD-ROM)  4th-  ROMBUNNO.IA,YAMAMOTOTAKASHI,1  2013  [Not refereed][Not invited]
  • Elliott L. Hazen, Robert M. Suryan, Jarrod A. Santora, Steven J. Bograd, Yutaka Watanuki, Rory P. Wilson  MARINE ECOLOGY PROGRESS SERIES  487-  177  -183  2013  [Not refereed][Not invited]
     
    Identifying areas of high species diversity and abundance is important for understanding ecological processes and conservation planning. These areas serve as foraging habitat or important breeding or settlement areas for multiple species, and are often termed 'hotspots'. Marine hotspots have distinct biophysical features that lead to their formation, persistence, and recurrence, and that make them important oases in oceanic seascapes. Building upon a session at the North Pacific Marine Science Organization (PICES), this Theme Section explores the scales and mechanisms underlying hotspot formation. Fundamentally, understanding the mechanisms of hotspot formation is important for determining how hotspots may shift relative to ocean features and climate change, which is a prerequisite for determining management priorities.
  • 西沢文吾, 綿貫豊, 齊藤誠一  水産海洋学会研究発表大会講演要旨集  2012-  92  2012/11/15  [Not refereed][Not invited]
  • バイオロギング技術を使った海鳥の海外共同研究
    綿貫豊, 佐藤克文, 高橋晃周  日本鳥学会誌 日本鳥学会100周年記念特別号  61-  61  -63  2012  [Not refereed][Not invited]
  • 環境変化と海鳥:気候と人間の影響
    綿貫豊  モーリー  29-  22  -24  2012  [Not refereed][Not invited]
  • 羽ばたき潜水で漁をする
    綿貫豊  バーダー  26-  30  -37  2012  [Not refereed][Not invited]
  • 福地光男, 谷村篤, 渡邉研太郎, 小達恒夫, 平譯享, 飯田高大, 高橋邦夫, 神田啓史, 綿貫豊, 内藤靖彦, 大山佳邦, 星合孝男  極域科学・宙空圏・気水圏・生物・地学シンポジウム講演予稿集(CD-ROM)  2011-  ROMBUNNO.B.M.FUKUCHIMITSUO  2011  [Not refereed][Not invited]
  • 日本でなぜ今海鳥を研究するのか
    綿貫豊  海洋と生物  194-  195  -198  2011  [Not refereed][Not invited]
  • 「カンムリウミスズメと上関(瀬戸内海)の生物多様性」国際シンポジウムの意義
    綿貫豊  科学  81-  503  -505  2011  [Not refereed][Not invited]
  • 北原祥, 佐藤克文, 坂本健太郎, DAUNT F, 綿貫豊  日本鳥学会大会講演要旨集  2010-  109  2010/09/01  [Not refereed][Not invited]
  • 小暮潔央, 佐藤克文, DAUNT Francis, 綿貫豊, 坂本健太郎, 山本誉士, 高橋晃周  日本生態学会大会講演要旨集  57th-  430  2010/03/15  [Not refereed][Not invited]
  • ヨーロッパヒメウの潜水と飛行:海鳥もニュートン力学には逆らえない
    綿貫豊  遺伝  64-  36  -41  2010  [Not refereed][Not invited]
  • Rory P. Wilson, Yutaka Watanuki, Nobuyuki Miyazaki, Brent S. Stewart  AQUATIC BIOLOGY  8-  (3)  191  -192  2010  [Not refereed][Not invited]
     
    This Theme Section looks at new approaches in the study of seabird foraging ecology, with particular emphasis on the use of recently developed recording devices attached to birds. It includes studies with energy as a theme, such as the energetics of foraging in Magellanic penguins, how dive efficiency varies with depth in emperor penguin, optimality of stroke frequency in diving seabirds, and how using energy to counteract depth-dependent buoyancy may limit pursuit speeds in hunting imperial shags. A more physiological approach is adopted in two studies, one on the dive capacity of emperor penguins and one on planktivorous auklets. Foraging ecology is examined more broadly in a study on the foraging behaviour of breeding thick-billed murres while a modelling approach is used to describe foraging profitability in aucklets (the smallest marine endotherms) feeding on pelagic patches. Finally, consideration is given to bird-attached instrument artefacts in path reconstruction of diving birds using dead-reckoning.
  • Climate induced phenological mismatch:an implication from a long-term monitoring study of seabirds
    60-  1  -116  2010  [Not refereed][Not invited]
  • 綿貫豊, 高橋晃周, TRATHAN PN, WANLESS S, 坂本健太郎, 佐藤克文  日本鳥学会大会講演要旨集  2009-  22  2009/09/01  [Not refereed][Not invited]
  • 海氷の減少とペンギン
    綿貫豊  私たちの自然  150-  18  -19  2009  [Not refereed][Not invited]
  • Japanese Journal of Ornithology  57-  (2)  148  -153  2008  [Not refereed][Not invited]
  • Kentaro Kazama, Kentaro, Q. Sakamoto, Yutaka Watanuki  Journal of the Yamashina Institute for Ornithology  39-  (2)  112  -116  2008  [Not refereed][Not invited]
  • 海水温および気温の年変化に対するウトウの反応とその将来予測
    綿貫豊  月刊海洋科学  39-  331  -335  2007  [Not refereed][Not invited]
  • Climate and marine birds and mammals in the North Pacific.
    Watanuki Y, Minobe S, Sydeman B  PICES Press  15-  18  -19  2007  [Not refereed][Not invited]
  • Tsushima current affects the diet and breeding of seabirds
    Watanuki Y  International Newsletter  October 2006-  40  -41  2007  [Not refereed][Not invited]
  • The influence of interannual variation in sea-surface temperature on the first egg date of Black-tailed Gulls at Teuri Island, Japan
    N. Tomita, M. Takagi, Y. Watanuki  JOURNAL OF ORNITHOLOGY  147-  (5)  264  -264  2006/08  [Not refereed][Not invited]
  • 気候変動と人間活動が海洋生態系に与える影響を海鳥の目で探る
    綿貫 豊  月刊海洋科学  37-  608  -613  2005  [Not refereed][Not invited]
  • KUME Atsushi, WATANUKI Yutaka  JAPANESE JOURNAL OF ECOLOGY  53-  (1)  39  -41  2003  [Not refereed][Not invited]
  • 海鳥の高い運動能力を解き明かす:海中と空中を飛行するハシブトウミガラスの採食行動
    綿貫豊  科学  73-  39  -44  2003  [Not refereed][Not invited]
  • 長谷川理, 高木昌興, 綿貫豊, 阿部周一  日本生態学会大会講演要旨集  49th-  281  2002/03/25  [Not refereed][Not invited]
  • 千田麻由, 新妻靖章, 高木昌興, 綿貫豊  日本生態学会大会講演要旨集  49th-  192  2002/03/25  [Not refereed][Not invited]
  • 内藤靖彦, 綿貫豊, 宮本佳則, 加藤明子, 市川秀雄, 荒井修亮, 西川淳, 佐藤克文, 黒木麻紀, 高橋晃周, 遠藤宣成, 岩見哲夫, 沼波秀樹  南極資料  46-  (2)  399  -413  2002  [Not refereed][Not invited]
  • 千田麻由, 新妻靖章, 高木昌興, 井関謙一, 綿貫豊  日本生態学会大会講演要旨集  48th-  135  2001/03/22  [Not refereed][Not invited]
  • 高木昌興, 陳有, 長谷川理, 帖地美千代, 綿貫豊  日本生態学会大会講演要旨集  47th-  199  2000/03/21  [Not refereed][Not invited]
  • アデリーペンギンの採餌および繁殖生態への海氷変動の影響
    加藤明子, 内藤靖彦, 綿貫豊  月刊海洋  31-  809  -813  1999  [Not refereed][Not invited]
  • 水中を飛ぶ鳥の不思議
    綿貫豊  野鳥  622-  6  -10  1999  [Not refereed][Not invited]
  • 魚資源とウトウの採食生態/多様な時スケールにおける反応
    綿貫豊  月刊海洋  30-  249  -254  1998  [Not refereed][Not invited]
  • ニホンザルにおけるエネルギー収支の性年齢間の差:秋と冬の比較
    綿貫豊, 中山裕理  ワイルドライフフオーラム  3-  51  -55  1997  [Not refereed][Not invited]
  • 海鳥たちの現状とヒューマンインパクトの排除
    綿貫豊  野鳥  29-  174  -180  1997  [Not refereed][Not invited]
  • 類における潜水時間の体重依存性と潜水中の体温低下
    綿貫豊, 加藤明子, 内藤靖彦  月刊海洋科学  29-  174  -180  1997  [Not refereed][Not invited]
  • 海氷とアデリーペンギンの生活
    綿貫豊  極地  63-  39  -42  1996  [Not refereed][Not invited]
  • 環境変動モニターとしてペンギンの生活を調べる
    綿貫豊, 一井太郎  遺伝  48-  23  -27  1994  [Not refereed][Not invited]
  • 肺呼吸する潜水動物のジレンマ
    綿貫豊  どうぶつと動物園  44-  4  -7  1992  [Not refereed][Not invited]
  • ダイバーとしてのペンギン
    綿貫豊  日経サイエンス  22-  29  1992  [Not refereed][Not invited]
  • ユルリ、モユルリ両島における鳥類相の変化
    近藤憲久, 橋本正雄, 綿貫豊  根室市博物館準備室紀要  1-  33  -46  1986  [Not refereed][Not invited]
  • 北海道の海岸で繁殖する鳥たち
    綿貫 豊  野鳥  468-  18  -19  1985  [Not refereed][Not invited]
  • 北海道周辺におけるオオセグロカモメの繁殖期の食性
    綿貫 豊  月刊海洋科学  16-  212  -216  1984  [Not refereed][Not invited]
  • 海鳥における捕食と餌の略奪
    綿貫 豊  個体群生態学会会報  37-  67  -76  1983  [Not refereed][Not invited]
  • ハシブトウミガラスの潜水行動を探る
    綿貫豊  バーダー  122-  (3)  71  -73  [Not refereed][Not invited]
  • バイオテレメトリー技術によって海でのペンギンの潜水生理と採食行動を研究する
    綿貫豊  海洋と生物  116-  190  -196  [Not refereed][Not invited]
  • コロニーでのアデリーペンギンのカウント:季節変化と年変化
    綿貫豊, 内藤靖彦  南極資料  36-  279  -284  [Not refereed][Not invited]

Awards & Honors

  • 2009/03 日本生態学会 大島賞
  • 2009/02 PacificSeabird Group Special Achievement Award

Research Grants & Projects

  • 海洋プラスチックごみ及びその含有化学物質による生態影響評価
    環境省:環境省環境研究総合推進費
    Date (from‐to) : 2018/04 -2021/03 
    Author : 高田秀重
  • 洋上風力発電の建設から主要な海鳥繁殖地を守るセンシテイビテイマップの開発
    環境省:環境省環境研究総合推進費
    Date (from‐to) : 2018/04 -2021/03 
    Author : 関島恒夫
  • 風力発電施設の建設による鳥衝突のリスク低減を目指した高精度鳥感度Mapの開発
    環境省:環境省環境研究総合推進費
    Date (from‐to) : 2016/04 -2018/03 
    Author : 関島恒夫
  • 渡りと遺伝的分化に着目したアホウドリの保全単位の解析
    文部科学省(日本学術振興会):科学研究費補助金(挑戦的萌芽)
    Date (from‐to) : 2015/04 -2018/03 
    Author : 綿貫 豊
  • 動物装着ビデオを用いた漁船と海鳥の個体レベルでの相互作用の研究
    文部科学省(日本学術振興会):科学研究費補助金(基盤B海外)
    Date (from‐to) : 2014/04 -2017/03 
    Author : 綿貫 豊
  • 隠れた沿岸海洋ホットスポットを発見する技術の開発
    文部科学省(日本学術振興会):科学研究費補助金(挑戦的萌芽研究)
    Date (from‐to) : 2013/04 -2015/03 
    Author : 綿貫 豊
  • 海鳥類の食性・分布特性の解明
    水産庁:国際資源評価など推進事業
    Date (from‐to) : 2010/04 -2014/03 
    Author : 綿貫 豊
  • 海鳥を食物網と汚染のトレーサーとした海洋生態系モニタリング
    文部科学省(日本学術振興会):科学研究補助金(基盤A)
    Date (from‐to) : 2007/04 -2013/03 
    Author : 綿貫 豊
  • 外洋性アホウドリ類の混穫軽減を目的としたGPS及び映像を使った行動研究
    文部科学省(日本学術振興会):科学研究費補助金(挑戦的萌芽研究)
    Date (from‐to) : 2006/04 -2009/03 
    Author : 綿貫 豊
  • 加速度のマイクロ計測による潜水性海鳥の最適採食行動の研究
    文部科学省(日本学術振興会):基盤研究(B)
    Date (from‐to) : 2005/04 -2008/03 
    Author : 綿貫 豊
  • 野生動物とペット・家畜の土地利用管理のための超小型GPSロガーによる動物行動研究
    双葉電子記念財団:双葉電子記念財団研究助成
    Date (from‐to) : 2004/04 -2005/03 
    Author : 綿貫 豊
  • 高速で3次元的に海洋環境を利用する高次捕食者の方位と水温測定による索餌経路の解析
    文部科学省(日本学術振興会):科学研究費補助金(萌芽研究)
    Date (from‐to) : 2002/04 -2004/03 
    Author : 綿貫 豊
  • 短期的体温低下が活動中の内温性動物のエネルギー節約に果たす適応的意義
    文部科学省(日本学術振興会):科学研究費補助金(基盤C)
    Date (from‐to) : 1999/04 -2001/03 
    Author : 綿貫 豊
  • 高次捕食者をプラットフォームとした海洋環境変動のモニタリング
    文部科学省(日本学術振興会):科学研究費補助金(基盤C)
    Date (from‐to) : 1997/04 -1999/03 
    Author : 綿貫 豊
  • 海鳥をデバイスとした海洋環境変動のモニタリング
    文部科学省(学術振興会):科学研究費補助金(奨励A)
    Date (from‐to) : 1995/04 -1996/03 
    Author : 綿貫 豊
  • ウ類の潜水捕食戦略
    住友財団:住友財団基礎科学研究助成金
    Date (from‐to) : 1992/04 -1994/03 
    Author : 綿貫 豊

Educational Activities

Teaching Experience

  • 資源生物学実験
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 水産学部
  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
  • 特別実習Ⅰ
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 水産学部
  • English for Fisheries Sciences I
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 海洋生物学、資源生物学、海洋環境化学、海洋共生学
  • 特別実習Ⅱ
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 水産学部
  • Marine Environment Conservation
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : (綿貫) 最大持続生産・保全生物学 (松石)水産資源,資源管理 (工藤,芳村)栄養塩環境,海洋酸性化,生物応答 (東条) 持続可能性・バリューチェーン (藤森) 漁業管理・持続的漁業・混獲 (バウア) 持続可能性と海洋漁業
  • Marine Science Biology IV - Laboratory
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 海生哺乳類 海鳥 多様性 形態
  • Marine Ecology
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 水産学部
    キーワード : 海洋生態系,資源変動,人間活動,気候変化,高次捕食者,食物連鎖,空間スケール,再生産機構,レジームシフト,保全,水産資源の持続的利用,順応的漁業(資源)管理
  • Environment and People
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 海洋環境,海洋生態系,環境変化,プランクトン,ベントス,魚類,イカ・タコ類,鯨類,海鳥類,海獣類,海藻,衛星海洋学,生態系モデル,人間活動,地球温暖化,海洋動物の保全・保護


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