Distinguishing Characteristics

Small plover (length 170–190 mm; mass about 47 g). In Alternate (breeding) plumage, upperparts medium brown; underparts white, with white collar around neck, bordered posteriorly by single black breast-band that extends around neck; forehead white; forecrown and sides of head black; and narrow postocular stripe white. Wings and tail dark, with single narrow white stripe on wing along base of remiges. Bill short and stubby; legs short. Bill black, with yellow to orange base; legs dull yellow to orange; bare skin around eye yellow to orange, producing narrow eye-ring (Paulson 1993). Sexes similar, but female usually has brown feathers in crown, mask, and breast-band (Dunn 1993, Teather and Nol 1997, MSB), bolder postocular stripe (stripe is less conspicuous or sometimes absent in male; Hayman et al. 1986, MSB), and duller orange bill (Teather and Nol 1997). Basic (winter) plumage is similar to Alternate plumage, but black on head and breast-band is mostly replaced by gray-brown, white postocular stripe is more extensive, sometimes joined to white forehead to form supercilium, and wing-coverts are narrowly fringed whitish when fresh. Sexes are similar, but males have greater amount of black on sides of head and forecrown (A. Smith pers. comm.). Juvenal plumage is similar to Basic adult plumage, but more extensively white, especially on supercilium and wing-stripe; feathers of upperpart have narrow dark subterminal bands and extensive buff fringes (Hayman et al. 1986), and bill is extensively or entirely black (Cramp and Simmons 1983). Chicks are downy and well camouflaged, with irregularly spotted black and buffy-gray down feathers on upperparts, narrow black margins, buffy streaks on sides and back, dull-white underparts with narrow dark breast-band, white forehead, and wide white collar around neck (Snyder 1957).

Several other species of North and Central American plovers have plumage patterns similar to that of the Semipalmated Plover, but they differ as follows. Wilson’s Plover (Charadrius wilsonia) is distinctly larger and has proportionally larger, more robust head, and longer, thicker bill; Snowy Plover (C. alexandrinus) has incomplete breast-band, paler upperparts, and black legs; Piping Plover (C. melodus) has much paler upperparts and (usually) incomplete breast-band; Collared Plover (C. collaris) is slightly smaller and has more reddish upperparts, narrower, longer bill, flesh-colored legs, and dark hindneck (Paulson 1993, Howell and Webb 1995). Young Killdeer (C. vociferus) just molting into Juvenal plumage also has a single breast-band and superficially resembles Semipalmated Plover, but it is distinguished by fuzzy appearance, which results from presence of many downy feathers (Paulson 1993).

Semipalmated Plover is extremely similar in size and appearance to Common Ringed Plover, a species that breeds in the North American Arctic but rarely occurs in North America outside of this area (Dunn 1993). In Alternate plumage, Common Ringed Plover differs as follows: Postocular stripe averages longer and thicker (but relative size of stripe differs between the sexes as in Semipalmated Plover); white patch on forehead is larger and usually more pointed at rear; black on head is more extensive; and orbital ring is incomplete or dark orange and less prominent (Walsh 1985, Paulson 1993). In Juvenal and Basic plumages, these species are even more difficult to distinguish. Differences that help distinguish Common Ringed Plover from Semipalmated Plover in any season include the following: Breast-band averages wider, wing-stripe is more distinct, bill is slightly longer and culmen slightly straighter, and call note is a mournful poo-wee (whereas that of Semipalmated Plover is a clear, fairly sharp whistle with rising inflection: chee-wee or chuwit; calls of both species are similar in pitch; Hayman et al. 1986, Dunn 1993, Paulson 1993). At very close range or in the hand, Common Ringed Plover has webbing only between inner and middle front toes, whereas Semipalmated Plover has webbing between all 3 front toes. Inner web of second innermost secondary is also white in Common Ringed Plover, but washed with brown in Semipalmated Plover; on the outer 3 primaries, white extends slightly onto outer webs in Common Ringed Plover, but white restricted sharply to primary shaft in Semipalmated Plover (Hayman et al. 1986).

Mullarney (1991) reported that in juvenile Semipalmated Plovers, lower edge of dark coloration below eye intersects bill in line above gape, close to culmen, but that this area intersects bill at gape in juvenile Common Ringed Plovers. However, some Semipalmated Plovers are identical to Common Ringed Plovers in this respect (Dunn 1993). Semipalmated Plover chicks are reported to have darker downy feathers on head and back on average than Common Ringed Plover chicks (Smith 1969, Baicich and Harrison 1997).

Semipalmated Plover is also similar to Little Ringed Plover (Charadrius dubius), a casual visitor to North America, recorded several times in w. Aleutian Is. Little Ringed Plover is distinguished by more slender appearance, relatively longer tail and legs, and slimmer bill, as well as lack of clear wing-bar; thicker, brighter eye-ring (conspicuous at all ages), mostly dark bill; dull yellowish or dull pink legs; and different voice (far-carrying pee-oo).

For additional information on identification, see Hayman et al. 1986 and Paulson 1993 .