Average size :  36 to 43 cm (14 to 17 in), males 601 g (21 oz) and females 516 g (18 oz)

Coloration :  Cryptic coloration, varies with the season; summer plumage mottled with black, dark brown, grayish-brown and buff; white wings and feet; black tail; male with rust-colored head, neck and breast.; lighter colored belly and dewlaps redder than in the female; winter plumage white with black tail; molting plumage with white patches.

External characteristics :   Short, stout beak; feathered nares; short, rounded wings; fully feathered feet.