King eider foraging effort during the pre-breeding period in Alaska

The Condor
By: , and 

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Abstract

For reproduction, many arctic-nesting migratory birds rely on nutrients obtained on the breeding grounds, so they devote sufficient time to foraging immediately prior to nesting. However, little is known about the increase in foraging effort necessary to meet the energetic requirements of reproduction. In early June 2006 and 2008, we quantified the proportion of time spent foraging before breeding by a large sea duck, the King Eider (Somateria spectabilis), on its breeding grounds in northern Alaska. During >235 hours of behavioral observations, both male and female King Eiders spent >50% of the day loafing (resting, sleeping, comfort behavior, or being alert). Females foraged on average 30% of the time (mean 7.2 hr day-1,95% CI 6.0-8.4 hr day-1), three times as much as males (9%; 2.3 hr day-1, 95% CI 1.5–2.8 hr day-1). The most common prey in ponds where the eiders foraged were chironomid larvae and worms ranging in length from 1 to 30 mm. If the King Eider's daily energy expenditure on its breeding grounds is similar to values published for related species, it would need to ingest only 0.2–0.6 g dry mass of invertebrates per minute of foraging to meet its energetic requirements. Males did not lose body mass before breeding, and we assume that their foraging effort was sufficient for energy balance. Therefore, female King Eiders appear to triple their foraging effort over maintenance requirements to meet the energetic challenges of egg formation.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title King eider foraging effort during the pre-breeding period in Alaska
Series title The Condor
DOI 10.1525/cond.2011.100077
Volume 113
Issue 1
Year Published 2011
Language English
Publisher Cooper Ornithological Society
Contributing office(s) Coop Res Unit Leetown
Description 9 p.
First page 52
Last page 60
Country United States
State Alaska
Other Geospatial Teshekpuk Lake
Online Only (Y/N) N
Additional Online Files (Y/N) N
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