Identification

17–22 cm; male 53–114 g, female 39–105 g; wingspan 36–43 cm. Medium-sized sandpiper with a rufous cap and dark brown upperparts with chestnut and whitish-buff fringes. The neck and breast are heavily streaked; the lower breast, upper belly, and flanks with heavy blackish chevrons. The legs are yellowish to greenish or brownish, with the bill black with a brownish or pinkish base of the lower mandible. In flight, it shows a narrow white wingbar and white sides to dark-centered rump and uppertail coverts. The female is smaller (by 5–10%) and especially shorter winged. Nonbreeding adults lack warm coloration; the breast is grayish with faint streaks, indistinctly demarcated from white belly . The juvenile has bright buff, chestnut, and whitish fringes on the upperparts, a rufous crown, and a conspicuous white supercilium. The breast is bright buff, sometimes with faint streaks forming a narrow gorget. The flanks are washed buff; becoming duller with age.

The Sharp-tailed Sandpiper is similar to the Pectoral Sandpiper (Calidris melanotos), but it is more rufous, with a rufous wash to breast without a sharp demarcation of the breast from the belly. The Sharp-tailed Sandpiper also has a more conspicuous ginger cap, a bolder white supercilium, and a prominent eyering. Its underparts are less streaked than the Pectoral Sandpiper; however, the rump-sides are more streaked. The bill is slightly shorter and more straight, and it has marginally shorter legs and a more pot-bellied appearance.