Migration ecology and distribution of king eiders

Abstract

Alaskan-breeding king eiders (Somateria spectabilis) disperse from nesting areas on the Arctic Coastal Plain and move through the Beaufort Sea to wing molt and winter locations in remote areas of the Bering Sea. Knowledge of king eider distribution outside the breeding period is critical to provide regulatory agencies with opportunities to minimize potential negative impacts of resource development. To characterize the nonbreeding distribution of king eiders, we collected location data of 60 individuals over two years from satellite telemetry. During post-breeding migration, male king eiders had much broader use areas in the Alaskan Beaufort Sea than female eiders. Chronology of wing molt was earlier for males than females in all years. Throughout wing molt and winter, eider locations were closer to shore, in shallower water with lower salinity than randomly selected locations. Short residence time of king eiders in deep water areas suggests the Alaskan Beaufort Sea may not be as critical a staging area for eiders during spring as it is during post-breeding. This study provides some of the first large-scale descriptions of king eider migration, distribution, and habitat outside the breeding season.