Size: L: 70 cm. Wt: 700g. Males and females similar. This species not seasonally dimorphic.

Adult: body mostly various shades of brown; black "moustache" streaks; heavy brown streaking on paler breast; legs and feet greenish-yellow; dark flight feathers.

Juvenile: similar to adult, but moustache streaks absent.

Nestling: semialtricial and downy; down yellowish-olive, darker above than below; bill flesh-coloured with dark tip; eyes light olive