Populations, feeding ecology and molt of Steller's Eiders

The Condor
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Abstract

This study considers the temporal and spatial distribution of Steller's Eiders (Polysticta stelleri) during molt along the north side of the Alaska Peninsula from Port Heiden to Bechevin Bay. Subadult eiders molted primarily at Nelson Lagoon, adult males at Nelson Lagoon and Izembek Bay, and adult females primarily at Izembek Bay. Only a few eiders used Bechevin Bay, Seal Islands, and Port Heiden. Although the flightless period overlapped among different age and sex classes, subadults were flightless first, then adult males, and last, adult females. Eiders maintained spatial and temporal separation during the flightless period, thereby reducing competition for food resources.

Eiders at Nelson Lagoon were observed feeding only by head-dipping during the pre-flightless period in 1979, a significant change from 1977 when they fed both by diving and dipping. During both 1977 and 1979 eiders foraged for approximately equal amounts of time during each stage of molt. Foods consisted primarily of bivalve mollusks and amphipods. These foods were consumed in different proportions before and after the wing-feather molt, with mussels being most important when eiders were growing remiges. Comparisons between the amount of energy in blue mussels (Mytilus edulis), clams (Macoma balthica), and gammarid amphipods showed that mussels yield the most energy per gram of whole wet weight. Apparently Steller's Eiders have adjusted to the increased energy demands of molt by eating invertebrates with high caloric content, rather than by increasing the amount of time feeding.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Populations, feeding ecology and molt of Steller's Eiders
Series title The Condor
DOI 10.2307/1367319
Volume 83
Issue 3
Year Published 1981
Language English
Publisher Cooper Ornithological Society
Contributing office(s) Alaska Science Center, Alaska Science Center Biology WTEB, Western Fisheries Research Center
Description 7 p.
First page 256
Last page 262
Country United States
State Alaska
Other Geospatial Alaska Peninsula
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