The sooty falcon is an attractive, medium-sized bird of prey with long, slender wings and a long tail (4). Although the adult plumage is mainly uniform grey, in the male it is pale with a bluish tinge, while in the female it is a darker, sooty shade. Both the flight-feathers and the area below the eyes are significantly darker than the rest of the body, and some individuals possess a small pale patch on the throat (2). In contrast to the dark plumage, the bare areas on the legs, around the base of the bill and the rim around the eyes are bright yellow (5). The juvenile's plumage differs quite significantly from that of the adult's. The head and nape are light brownish, the upperparts are brownish-grey edged with yellowish-white feathers, while the underparts are brown and heavily streaked with brownish-grey (2). A dark stripe extends from the base of the bill, and the throat and lower cheeks are cream coloured (2) (5). By its first summer, the juvenile undergoes a considerable change in colouration becoming a much darker, uniform grey than the adult, with conspicuous dark barring on the undersides of the wings and tail (2).