This species gets its name from its white uppertail coverts, but this mark is usually only visible when the bird is in flight. In all plumages, the wing tips extend well beyond the tail. The bill is fairly short and straight, and black with a pale reddish base to the lower mandible. The legs are black. Alternate Adult: Upperparts are gray-brown with pale brownish feather edges and just a little rufous on the scapulars, crown and auriculars. A whitish supercilium is present but subtle. The head, neck, and breast are finely streaked with blackish, mixing with dark chevrons along the flanks. Basic Adult: Similar to Alternate Adult, but duller gray, lacking any rufous on upperparts. Breast streaking is not as crisp or extensive in this plumage. Juvenile: Bright rufous present on crown, scapulars, and tertials. Wing coverts show white edges, creating a neat scaly pattern. The underparts show dull streaking on the breast, usually not extending along the sides. Similar to juvenile Baird's Sandpiper, but more colorful on upperparts and lacking buffy tones on the head, neck, and breast.

Length: 18 (cm) Wingspan: 36 (cm)

Voice:

Call is a high jeet.

Habitat:

Nests on tundra. In migration, uses mudflats, beaches, lake shores.

Behavior:

Forms large flocks. Often intermingles with other species.

Feeding:

Moves slowly as it probes in mud and shallow water for invertebrates.