Distinguishing Characteristics

Adult male American Golden-Plover on breeding territory, Churchill, MB, 23 June.

Female American Golden-Plover in alternate (breeding) plumage on tundra nesting grounds near Nome, AK, June.

Juvenile American Golden-Plover, Forsythe NWR, NJ, 8 November.

Juvenile American Golden-Plover, Salinas, CA, 23 October.

Juvenile American Golden-Plover (front right) with Pacific Golden-Plovers near Nome, AK, 21 August.

Description

Medium-sized plovers. The following features helpful but not infallible in separating species: length of American Golden-Plover (24–28 cm) frequently exceeds that of Pacific Golden-Plover (23–26 cm); although ranges overlap for all standard measurements (see Johnson and Johnson 2004; Appendices 1 and 2, below ), flattened wing in Pacific Golden-Plover typically <175 mm, in American Golden-Plover >180 mm; Pacific Golden-Plover tends to have slightly longer bill and tarsus, also tibia more exposed and less feathered proximally, giving bird somewhat longer-legged appearance than American Golden-Plover; in all plumages, Pacific Golden-Plover upperparts spangled with bright yellow markings on dark grayish-brown background, American Golden-Plover upperparts similar but less colorful. The most reliable field criteria for identifying the two species (Johnson and Johnson 2004) are: interspecific differences in breeding plumages (see below) during spring and part of the summer; exposure of primary tips beyond the longest tertials on folded wing, typically 2-3 in Pacific Golden-Plover, 4–5 in American Golden-Plover; primary tip projection past end of the tail least in Pacific Golden-Plover (around 0-9 mm), greatest in American Golden-Plover (about 12-22 mm). Individual variation often associated with molting during the nonbreeding season will make some individuals (as in puzzling extralimital situations) impossible to identify with certainty (Hayman et al. 1986, Dunn et al. 1987, Marchant and Higgins 1993, Paulson 1993, Kaufman 2000, Johnson and Johnson 2004).

Identification

Most males in Alternate plumage easily separable to species: white neck stripe of American Golden-Plover terminates abruptly at upper breast, and flanks and undertail-coverts black; in Pacific Golden-Plover, white continues past the breast forming an irregular but conspicuous wash along sides and flanks, and undertail-coverts predominantly white. The extent of lateral whiteness varies among male Pacific Golden-Plovers making some individuals showier than others. Female Alternate plumage less colorful, with varying numbers of whitish feathers on breast and face producing mottled appearance. Obvious sexual dimorphism typical in Pacific Golden-Plover and in most American Golden-Plovers; some American Golden-Plover females less mottled, darker (brownish black), nearly male-like in appearance. Basic and juvenal plumages are generally distinctive: head, neck, breast, and upperparts grayish in American Golden-Plover, bright yellowish-buff in Pacific Golden-Plover. However, subtle variation in juvenal and nonbreeding plumage coloration sometimes renders this feature misleading (Connors 1983, Dunn et al. 1987, Golley and Stoddart 1991, Marchant and Higgins 1993, Paulson 1993, Beaman and Madge 1998).

American and Pacific golden-plovers are both smaller than Eurasian Golden-Plover (Pluvialis apricaria). Also, Eurasian Golden-Plover has mostly white wing-linings, whereas underwing of American and Pacific golden-plovers is smoky gray. Black axillars, white wing stripe, white rump and uppertail distinguish the Black-bellied Plover (Pluvialis squatarola) in all plumages from the golden-plovers. Compared to the latter, alternate plumage of Black-bellied Plover is particularly distinctive with silver-gray on upperparts, white undertail, and more extensive white on head, neck, and shoulders.

Weights similar in both species but extremely variable (about 100–200+ g) with annual cycle. Abnormally low weights occur in some Pacific Golden-Plovers (usually juveniles) encountering stressful conditions during fall migration; emaciated individuals at or near death may drop to 50-70 g (Johnson et al. 1989, Johnson et al. 2004c). Similar weight loss likely in American Golden-Plovers; an 86 g juvenile reported in Caribbean (Cramp and Simmons 1983).