Small population size of Pribilof Rock Sandpipers confirmed through distance-sampling surveys in Alaska

Condor
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Abstract

The Rock Sandpiper (Calidris ptilocnemis) is endemic to the Bering Sea region and unique among shorebirds in the North Pacific for wintering at high latitudes. The nominate subspecies, the Pribilof Rock Sandpiper (C. p. ptilocnemis), breeds on four isolated islands in the Bering Sea and appears to spend the winter primarily in Cook Inlet, Alaska. We used a stratified systematic sampling design and line-transect method to survey the entire breeding range of this population during springs 2001-2003. Densities were up to four times higher on the uninhabited and more northerly St. Matthew and Hall islands than on St. Paul and St. George islands, which both have small human settlements and introduced reindeer herds. Differences in density, however, appeared to be more related to differences in vegetation than to anthropogenic factors, raising some concern for prospective effects of climate change. We estimated the total population at 19 832 birds (95% CI 17 853–21 930), ranking it among the smallest of North American shorebird populations. To determine the vulnerability of C. p. ptilocnemis to anthropogenic and stochastic environmental threats, future studies should focus on determining the amount of gene flow among island subpopulations, the full extent of the subspecies' winter range, and the current trajectory of this small population.

Publication type Article
Publication Subtype Journal Article
Title Small population size of Pribilof Rock Sandpipers confirmed through distance-sampling surveys in Alaska
Series title Condor
DOI 10.1525/cond.2012.110109
Volume 114
Issue 3
Year Published 2012
Language English
Publisher Cooper Ornithological Society
Publisher location Washington, D.C.
Contributing office(s) Alaska Science Center Biology WTEB
Description 8 p.
First page 544
Last page 551
Country United States
State Alaska
Online Only (Y/N) N
Additional Online Files (Y/N) N
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