Size: L: 22 cm. Wt: Males: 50 g. Females: 60 g. Males and females are dimorphic in size, and in color during the breeding season, with females being more intensely-colored. This species is also seasonally dimorphic.
Breeding Female: upperparts blackish-brown, with prominent, tawny-orange stripe on scapulars, and tawny scalloping over wings; head chestnut, with blackish crown and nape, and large, circular, white eye patch; neck, breast, belly, and undertail coverts chestnut; bill yellowish, with black tip; legs dark
Breeding Male: similar in pattern to breeding female, but overall much paler; crown and nape brown, and eye patch with indistinct edges
Winter Adult: upperparts slate blue; head white, with dark slate on back of head and on nape; dark line runs back and downward from eye; crown, forehead, and throat white; breast and belly whitish, may appear very pale grey; bill and legs dark
Juvenile: wings blackish, with tawny feather-edges; back tawny, with black streaking; head whitish, with mottled tawny and blackish crown and nape, and dark smudge behind eye; throat white; foreneck, breast, and flanks pale brown; belly and undertail coverts whitish or greyish; bill and legs as in winter adult