King eider foraging effort during the pre-breeding period in Alaska
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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.
Study Area
| 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 |
| Google Analytic Metrics | Metrics page |