Charadrius wilsonia Ord
Thick-billed Plover (Corbat 2000).
Breeder. Rare and local in spring, summer, and fall in Gulf Coast region. HIGHEST CONSERVATION CONCERN.
A medium-sized (16.5-20.0 cm [6.5-7.9 in.]; Corbat 2000) plover readily distinguished from other ringed plovers by stout black bill; upperparts gray-brown, underparts white, and legs flesh-colored. Has a white forehead connecting a white supercilium and white hindneck collar. White eye-ring contrasts with dark eyes and ear coverts. In breeding males, breast band, forecrown, and lores black; in females they are gray-brown. Nonbreeding adults and juveniles similar to females, but breast band may be incomplete and birds may appear grayer overall. Call a high-pitched whistled whit or wheet. Alarmed birds may give an urgent, repeated quit call (Corbat 2000). Three subspecies recognized; two occur in North America, C. w. wilsonia in the east and C. w. cinnamonius in the west. C.w. wilsonia is a breeding summer resident in Alabama (Corbat 2000).
Coastal areas from Virginia south to the Florida Keys, and west along the GulfCoast to northern Veracruz, Mexico. Also nests along Yucatan, Mexico. Breeds locally south of Yucatan into Central and South America on the AtlanticCoast to Brazil. Also breeds in the Bahamas and islands of the Greater and Lesser Antilles. PacificCoast pairs nest along the coast of Baja California south into central Mexico. Main wintering areas include both coasts of central Florida, western Louisiana, and Texas south into the remainder of its breeding distribution. Pacific birds winter south of breeding distribution in central Mexico into Central and South America. C. w. wilsonia breeds along the Atlantic and GulfCoasts from Virginia to Mexico and winters from Florida to Belize (Marchant 1986, Corbat 2000)
Coastal sites with sparse vegetation including sand dunes, beaches, sandflats, and barrier islands. Postnesting or migrating birds can be found in areas of open flat beaches with tidal pools. Wintering birds use beaches with tidal mudflats (Imhof 1976, Corbat 2000).
Crustaceans are a major food, especially fiddler crabs (Corbat 2000). Shrimp, mollusks, and flies also are consumed (Imhof 1976).
LIFE HISTORY AND ECOLOGY:
By early spring, birds arrive on breeding grounds and pair bonds may form before territories are established. Males create multiple nest scrapes on territories, but females choose nest sites (Bergstrom 1988). Nest is a shallow depression with added bits of shell, often built in open areas with scattered vegetation behind primary dunes. Typically, three pale buff eggs marked with dark speckles, splotches, and scrawls are laid. Produce one brood per year, but renesting occurs if nesting fails (Corbat 2000). Broken wing displays used in attempt to divert potential predators from nest. Both parents incubate eggs for about 25 days. Young feed themselves within a few hours of hatching, and become independent around 21 days. Alabama birds typically depart for wintering areas by October.
BASIS FOR STATUS CLASSIFICATION:
Although no population trend data exist, nesting birds are now absent from New Jersey and Maryland. Development of beachfront areas in the United States poses the greatest threat (Corbat 2000). Current estimates put the population around 6,000, although confidence in this figure is low (Brown 2000). Partners In Flight (PIF) considers Wilson’s plover a moderately high-priority species because it occurs at low relative abundance, has a limited breeding distribution, and threats to its breeding and nonbreeding grounds are expected to continue in the future (PIF 2002). Howell (1928) considered Wilson’s plover a “common summer resident” in Alabama. He listed a “half dozen pair or more” on DauphinIsland in 1912, although no nests were noted. Imhof (1976) indicated that 47 individuals were seen on DauphinIsland in August 1954. A pair of Wilson’s plovers has nested on PelicanIsland, a state-owned barrier island south of DauphinIsland, for the past several years. This has been the only documented nesting in Alabama in recent years (pers. obs.). Obviously nests in extremely low numbers in Alabama, but the coastal beaches provide important potential breeding habitat.