Size: L: 80-95 cm. Wt: Males: 4100 g. Females: 5200 g. Males and females are dimorphic in size, but similar in plumage colour. This species is not seasonally dimorphic.

Adult: head and tail white, tail rounded; upperparts dark brown, with rounded, slotted wings; underparts dark brown; bill massive, hooked, yellow; legs yellow, with large, taloned feet

Immature (1 to 4 years of age): body overall dark brown, with variable amounts of white scattered through feathers of underwing, undertail, and belly in flight; bill massive, hooked, grey; legs as in adult

Nestling: semialtricial and downy; first down grey, slightly paler on head and underparts; second down drab dark brown; bill large, hooked, blackish, with yellow cere; legs yellow, with taloned feet