Size: L: 50 cm. Wt: Males: 1250 g. Females: 1150 g. Sexually dimorphic in colour, but only slightly in size. Males of this species exhibit eclipse plumage.

Male: head dark chestnut; eye red; bill black, forming continous slope with forehead; breast black; flanks white; back pale grey; tail black.

Female: head and breast light brown; pale eye stripe; bill black, forming continous slope with forehead; flanks pale buff; back and tail grey.

Eclipse Male: similar to female.

Nestling: precocial; down dark brown above and over back of head and neck; trailing edge of wing and spots on lower back yellow; legs and bill dark, wedge-shaped bill apparent early in development, nail at tip of bill narrow