Proximity to multiple foraging habitats enhances seabirds’ resilience to local food shortages

Marine Ecology Progress Series

Rebecca Young¹  Rachael A. Orben¹  Alexander Kitaysky¹  Daniel D. Roby¹  Ann M. A. Harding¹  Robert M. Suryan¹  Rosana Paredes¹  David B. Irons¹  Heather Renner¹ 

关键词: GPS tracking;    Foraging strategies;    Marine habitats;    Kittiwakes;    Productivity;    Diet;    Nutritional stress;    Bering Sea;    Seabird populations;   

DOI  :  10.3354/meps10034

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: As central-place foragers, seabirds from colonies located close to multiple and/or productive marine habitats might experience increased foraging opportunities and enhanced resilience to food shortages. We tested whether this hypothesis might explain divergent trends in 3 populations of black-legged kittiwakes Rissa tridactyla, a surface-feeding piscivore, in the eastern Bering Sea. We simultaneously studied the foraging behavior, diet, nutritional stress, and breeding performance of chick-rearing kittiwakes from 2 continental shelf colonies (St. Paul and St. George) and an oceanic colony (Bogoslof). Although shelf-based forage fishes were rare or absent in bird diets during the cold study year, not all kittiwakes from the 3 colonies concentrated foraging along the productive shelf break habitats. Compared to the oceanic colony, birds from both shelf-located colonies had lower chick provisioning rates, higher levels of nutritional stress, and lower breeding performance. Although birds from both shelf-based colonies foraged in nearby neritic habitats during daytime, birds from St. George, a stable population located closest to the continental shelf break, also conducted long overnight trips to the ocean basin to feed on lipid-rich myctophids. In contrast, birds from St. Paul, a declining population located farthest from shelf break/oceanic habitats, fed exclusively over the shelf and obtained less high-energy food. Birds from Bogoslof, an increasing population, foraged mainly on myctophids close to the colony in the oceanic basin and Aleutian coast habitats. Our study suggests that proximity to multiple foraging habitats may explain divergent population trends among colonies of kittiwakes in the southeastern Bering Sea.

【 授权许可】

Unknown