Persistent annual migration patterns of a specialist seabird

Marine ecology progress series

Alexis P. Will^2,5¹  Abram B. Fleishman^3,4²  Takashi Yamamoto^2,6³  Rosana Paredes^7⁴  Rachael A. Orben^1⁵  Scott A. Shaffer^3⁶  Nobuo Kokubun^2⁷ 

[1] Conservation Metrics, Inc., 145 McAlister Way, Santa Cruz, CA 95060, USA^4;Department of Biological Sciences, San Jose State University, One Washington Square, San Jose, CA 95192-0100, USA^3;Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA^5;Department of Fisheries and Wildlife, 104 Nash Hall, Oregon State University, Corvallis, OR 97331-3803, USA^7;Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Dr., Newport, OR 97365, USA^1;Graduate School of Environmental Studies, Nagoya University, Nagoya, Aichi 464-8601, Japan^6;National Institute of Polar Research, Tachikawa, Tokyo 190-8518, Japan^2

关键词: Feather corticosterone;    Life-history trade-off;    Geolocation;    Migration;    Net‑;    squared displacement;    Stable isotopes;    Red-legged kittiwake;    Rissa brevirostris;   

DOI  :  10.3354/meps12459

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

Specialization can make animals vulnerable to rapid environmental changes. For long-lived seabirds, foraging specialization may make individuals especially sensitive, as climatic changes are currently occurring over the course of one lifetime. The Bering Sea is a dynamic subarctic and arctic ecosystem where windblown sea ice mediates annual productivity and subsequent pathways to upper trophic levels. Red-legged kittiwakes Rissa brevirostris are endemic surface foraging seabirds specializing on myctophid fishes during reproduction. Their degree of specialization outside the breeding season is less understood. We examined their non-breeding ecology (migration, distribution, isotopic niche) during 4 winters with varying sea ice extent. Although we found annual variation in core distributions, diets (as reflected in feather stable isotope signatures), and outbound migratory timing, the winter range of red-legged kittiwakes was restricted to the western regions of the Bering Sea and North Pacific. Contrary to expectations, sea ice did not limit distributions in the Bering Sea in 3 yr: e.g. sea ice associations (<100 km) were infrequent (8.7% mo-1). Yet, their wintering range often overlapped with areas of seasonal ice cover, suggesting range-wide use of sea ice ecosystems. Stress levels measured by corticosterone in feathers were generally low. However, birds that concentrated in the Bering Sea in February had higher stress levels and fed at a lower trophic level than those in the western Aleutians and western subarctic. As conditions change, this persistence in wintering locations, while incurring differential stress levels, may contribute to rapid population fluctuations as has been observed in the recent past.

【 授权许可】

Unknown