South polar skuas from a single breeding population overwinter in different oceans though show similar migration patterns

Seabirds in seasonal environments are often long-distance migrants and, for many spe-cies and populations, their ranges throughout the non-breeding period are unknown. As conditionsduring the non-breeding season often affect subsequent performance, the choice of migration strat-egy can have major implications for timing of breeding and success and, ultimately, populationdynamics. We tracked south polar skuas Catharacta maccormickifrom a single breeding populationat King George Island in the South Shetland Islands (Antarctica). Overall, 27 birds (69%) migrated tothe northern Atlantic (3 regions), 10 birds (26%) to the northern Pacific Ocean (2 regions), and 2 birdswintered in the southern hemisphere. Individuals tracked in consecutive non-breeding seasons chosethe same ocean for wintering. Despite migrating to different oceans, birds showed a similar figure-of-eight flight pattern and equivalent residency periods in the main wintering areas. In addition, 87% ofthe migrants used terminal stop-over sites off South America shortly before returning to the breedingsite. High diversity of migration patterns may buffer south polar skuas from climate change and otheranthropogenic threats.