The Pacific Coast western snowy plover (Charadrius alexandrinus nivosus) inhabits beaches, lagoons, and salt-evaporation ponds along the coasts of California, Oregon, and Washington, in the United States, and in Mexico  with the largest number of breeding birds occurring south of San Francisco Bay to southern Baja . Because of a decline in active nesting colonies and breeding and wintering populations the pacific coast population of snowy plovers was listed as threatened in 1993 . It is estimated that at the time the plover was listed, approximately 1,500 western snowy plovers nested in the United States . The decline of pacific coast snowy plovers has been attributed to loss of nesting habitat and habitat degradation caused by expanding beach-front development and recreation, human disturbance, encroachment of European beach grass on nesting grounds, and predation [1, 2].
Although the snowy plover still faces the same threats that it did prior to listing, protections have reduced the magnitude of these threats . Since listing, the number of snowy plovers and nesting sites appears to have increased and progress has been made toward bringing the species back to health . Measures taken to benefit plovers since listing include building exclosures to help reduce nest predation, restoring habitat by removing European beachgrass, posting signs and symbolic fencing around breeding sites, distributing information to the public, and increased law enforcement . In addition, 12,145 acres have been designated as critical habitat for snowy plovers (although this is about 40% less acreage than originally proposed) . Currently, the U.S. portion of the Pacific Coast population is estimated to have increased to approximately 2,300 .
California: Statewide surveys conducted in the late 1970s estimated the snowy plover population at 1,566 adults and found that only 20 of 53 historic breeding sites were occupied . Later, an additional 11 locations were identified as sites that had once supported, but subsequently lost, nesting plovers . Plover numbers continued to decline and in 2000 only 976 breeding plovers were observed . Since then, numbers have increased with 1,680 adult plovers observed during 2005 surveys . Ten new low density breeding sites have been identified, although at least 44 of the historic sites (many of which were high density sites) have still not had any recent nesting activity .
Oregon: Historically, snowy plovers nested at 29 coastal locations in Oregon . By the time the species was listed in 1993, 23 of these sites had been lost . Since listing, snowy plovers have reoccupied four of these sites bringing the number of breeding sites in the state up to ten . Since 1994, the number of adult breeding snowy plovers has been slowly increasing .
Washington: Plovers once nested at five coastal sites, but only three of these sites are currently active . Since listing, habitat conditions have improved at some sites and some additional habitat has been created . The number of breeding snowy plovers in the state has at least remained stable and may have increased since listing .
 U.S. Fish and Wildlife Service. Species Account: Western Snowy Plover. Website <http://ecos.fws.gov/docs/life_histories/B07C.html> accessed May, 2006.
 U.S. Fish and Wildlife Service. 2006. Background and Q&A’s about the West Coast Population of Snowy Plovers Website <http://www.fws.gov/sacramento/ea/news_releases/2006%20News%20Releases/Plover_petition-4d_2006_QA.html> accessed May, 2006.
 U.S. Fish and Wildlife Service. 1993. Determination of Threatened Status for the Pacific Coast Population of the Western Snowy Plover. Federal Register 58 FR 12864-12874.
 U.S. Fish and Wildlife Service. 2006. 12-Month Finding on a Petition to Delist the Pacific Coast Population of the Western Snowy Plover. Federal Register 71 FR 20607-20624.
 U.S. Fish and Wildlife Service. 2006. Western Snowy Plover Nesting Success Improves Again in 2005. New Release, November 4th, 2005. Available at <http://news.fws.gov/NewsReleases/showNews.cfm?newsId=5D35B69D-65BF-03E7-207B4B69FD517A95>.
 U.S. Fish and Wildlife Service. 2005. Critical Habitat Designated for Pacific Coast Population of the Western Snowy Plover. News Release, September 26, 2005. Available at <http://news.fws.gov/NewsReleases/showNews.cfm?newsId=93B3C371-65BF-03E7-2BFCCD9F7349AD9D>.