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Differential spring migration by male and female Western Sandpipers at interior and coastal stopover sites

Ardea

By:
, , and ORCID iD

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Abstract

Western Sandpipers Calidris mauri are differential migrants on their non-breeding areas, with females wintering farther south. Earlier passage of males in the spring has been explained by sexual differences in winter latitude (male-biased sex ratios at more northerly areas) and onset of migration (males departing earlier). We investigated sex differences during spring migration by capturing and radio-marking Western Sandpipers at two Pacific coast sites, San Francisco Bay, California and Grays Harbor, Washington and at a Great Basin interior wetland, Honey Lake, California. We monitored northward migration of 132 radio-marked birds at a network of 12 major stopover sites and 4 breeding areas. At the banding sites, we observed differences in sex by date and site, with males preceding females. We found sex differences in departure time of radio-marked birds from the banding site. their arrival time at the Copper River Delta, Alaska (our most frequently used stopover site), and in the likelihood that a stopover was used. Our data suggest that by mid to late April, migration timing becomes more compressed and sex differences are less pronounced and harder to detect.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Differential spring migration by male and female Western Sandpipers at interior and coastal stopover sites
Series title:
Ardea
Volume:
92
Issue:
2
Year Published:
2004
Language:
English
Publisher:
Netherlands Ornithologists' Union
Contributing office(s):
Western Ecological Research Center
Description:
12 p.
First page:
185
Last page:
196