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The article presents a study that investigated the foraging effort of King Eider during its pre-breeding period in northern Alaska. It says that King Eider is a large sea duck that breeds in arctic tundra ecosystems worldwide and spends most of its time at sea. It mentions that many arctic-nesting migratory birds rely on nutrients present on the breeding grounds. It relates that the study was conducted near the southeast shore of Teshekpuk Lake on the coastal plain of Alaska.

The article discusses a study on the impact of lipid extraction on stable isotope ratios in avian egg yolk. The procedure of the study started by collecting King Eider eggs in Alaska between 2006 and 2007. The laboratory techniques applied in the study include lyophilizing and homogenizing yolk samples. Steps to minimize analytical costs for species that likely derive lipids and proteins from the same source and environment are recommended.

Events during the non-breeding season may affect the body condition of migratory birds and influence performance during the following breeding season. Migratory birds nesting in the Arctic often rely on endogenous nutrients for reproductive efforts, and are thus potentially subject to such carry-over effects. We tested whether king eider ( Somateria spectabilis) arrival time and body mass upon arrival at breeding grounds in northern Alaska were affected by their choice of a winter region in the Bering Sea. We captured birds shortly after arrival on breeding grounds in early June 2002–2006 at two sites in northern Alaska and determined the region in which individuals wintered using satellite telemetry or stable isotope ratios of head feathers. We used generalized linear models to assess whether winter region explained variation in arrival body mass among individuals by accounting for sex, site, annual variation, and the date a bird was captured. We found no support for our hypothesis that either arrival time or arrival body mass of king eiders differed among winter regions. We conclude that wintering in different regions in the Bering Sea is unlikely to have reproductive consequences for king eiders in our study areas. [ABSTRACT FROM AUTHOR]