Size: L: 40 cm. Wt: Males: 415 g. Females: 305 g. Males and females are dimorphic in size, but similar in colour. This species is not seasonally dimorphic.
Adult: upperparts black, with olive or tawny streaking, with some chestnut on wing; head pale rufous, with dark crown and nape, and white chin and throat; breast and belly rufous; flanks with broad black and white barring; bill long, straight, with dark upper mandible and brownish lower mandible; legs olive-brown
Juvenile: upperparts black, with dark olive or dark tawny streaking; head pale gray-brown, with dark crown and nape, and whitish chin and throat; brest and belly pale gray-brown; flanks with broad gray-brown and white streaking; bill and legs as in adult
Nestling: precocial 4 and downy; down short, thick, black; legs and bill gray