Population Size of Snowy Plovers Breeding in North America

Abstract

Snowy Plovers (Charadrius nivosus) may be one of the rarest shorebirds in North America yet a com- prehensive assessment of their abundance and distribution has not been completed. During 2007 and 2008, 557 discrete wetlands were surveyed and nine additional large wetland complexes sampled in Mexico and the USA. From these surveys, a population of 23,555 (95% CI = 17,299 - 29,859) breeding Snowy Plovers was estimated. Com- bining the estimate with information from areas not surveyed, the total North American population was assessed at 25,869 (95% CI = 18,917 - 32,173). Approximately 42% of all breeding Snowy Plovers in North America resided at two sites (Great Salt Lake, Utah, and Salt Plains National Wildlife Refuge, Oklahoma), and 33% of all these were on wetlands in the Great Basin (including Great Salt Lake). Also, coastal habitats in central and southern Texas supported large numbers of breeding plovers. New breeding sites were discovered in interior deserts and highlands and along the Pacific coast of Mexico; approximately 9% of the North American breeding population occurred in Mexico. Because of uncertainties about effects of climate change and current stresses to breeding habitats, the spe-