Antarctic petrels ‘on the ice rocks’: wintering strategy of an Antarctic seabird

There is a paucity of information on the foraging ecology, especially individual use of sea-ice features and icebergs, over the non-breeding season in many seabird species. Using geolocators and stable isotopes, we defined the movements, distribution and diet of adult Antarctic petrels Thalassoica a...

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Bibliographic Details
Published in:Royal Society Open Science
Main Authors: K. Delord, A. Kato, A. Tarroux, F. Orgeret, C. Cotté, Y. Ropert-Coudert, Y. Cherel, S. Descamps
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 2020
Subjects:
geolocation
austral winter distribution
sea-ice concentration
iceberg
activity pattern
lunar cycle
Science
Q
Antarctic
Southern Ocean
Austral
Weddell
Svarthamaren
Antarc*
Antarctic Krill
Antarctica
Euphausia superba
Iceberg*
Sea ice
Thalassoica antarctica
Online Access:https://doi.org/10.1098/rsos.191429
https://doaj.org/article/395f6d60e8cd45a29ed99a8ebb0795f2
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Summary:There is a paucity of information on the foraging ecology, especially individual use of sea-ice features and icebergs, over the non-breeding season in many seabird species. Using geolocators and stable isotopes, we defined the movements, distribution and diet of adult Antarctic petrels Thalassoica antarctica from the largest known breeding colony, the inland Svarthamaren, Antarctica. More specifically, we examined how sea-ice concentration and free-drifting icebergs affect the distribution of Antarctic petrels. After breeding, birds moved north to the marginal ice zone (MIZ) in the Weddell sector of the Southern Ocean, following its northward extension during freeze-up in April, and they wintered there in April–August. There, the birds stayed predominantly out of the water (60–80% of the time) suggesting they use icebergs as platforms to stand on and/or to rest. Feather δ15N values encompassed one full trophic level, indicating that birds fed on various proportions of crustaceans and fish/squid, most likely Antarctic krill Euphausia superba and the myctophid fish Electrona antarctica and/or the squid Psychroteuthis glacialis. Birds showed strong affinity for the open waters of the northern boundary of the MIZ, an important iceberg transit area, which offers roosting opportunities and rich prey fields. The strong association of Antarctic petrels with sea-ice cycle and icebergs suggests the species can serve, year-round, as a sentinel of environmental changes for this remote region.

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