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Status of Spectacled Eiders (Somateria fischeri) on the Yukon-Kuskokwim Delta, Alaska, 2022—Testing and Updating Predictive Models

Open-File Report 2023-1052
Prepared in cooperation with the U.S. Fish and Wildlife Service
By:
https://doi.org/10.3133/ofr20231052

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Abstract

The nesting biology and demography of spectacled eiders (Somateria fischeri) along the lower Kashunuk River on the Yukon-Kuskokwim Delta, Alaska, were studied from 1993 to 2002. This previous work demonstrated that the breeding population on the study area was declining, and demographic modeling predicted that the population would continue to decline from 2002 forward. The predicted decline was primarily because of lead shot in tundra wetlands in the area, exposure of nesting females to lead, resulting in low adult female survival. The model predicted that lead pellets already in wetlands would slowly settle beyond the foraging depth of eiders, and that, lead exposure rates would decline. The goal of this project was to test this prediction by revisiting the lower Kashunuk River study area in 2022 to (1) update previous datasets regarding demographic parameters and (2) validate (or refute) existing models relative to lead exposure rates and the effects of lead on population dynamics. In the summer of 2022, a total of 37 nests were found in a sub-area of the historical study area. Comparing to past efforts in this same sub-area, more nests were found than predicted but the proportion of nesting female spectacled eiders exposed to lead in 2022 (24.3 percent) was still similar to levels of exposure observed between 1994 and 2002 (28.5 percent). Thus, data from the 2022 survey suggests that the earlier decline in numbers of nesting spectacled eiders has reversed, but there has been little decrease in lead exposure over time.

Suggested Citation

Flint, P.L., 2023, Status of spectacled eiders (Somateria fischeri) on the Yukon-Kuskokwim Delta, Alaska, 2022—Testing and updating predictive models: U.S. Geological Survey Open-File Report 2023–1052, 5 p., https://doi.org/10.3133/ofr20231052.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Methods and Study Area
  • Results
  • Discussion
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Status of spectacled eiders (Somateria fischeri) on the Yukon-Kuskokwim Delta, Alaska, 2022—Testing and updating predictive models
Series title Open-File Report
Series number 2023-1052
DOI 10.3133/ofr20231052
Year Published 2023
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Alaska Science Center Ecosystems
Description vi, 5 p.
Country United States
State Alaska
Other Geospatial Yukon-Kuskokwim Delta
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details