The lanner falcon is a handsome and powerful bird of prey, with grey-brown to slaty upperparts, a creamy-white throat and underparts, sometimes with dark spots or striping, and a characteristic reddish-brown crown on the head, which helps to distinguish it from the smaller peregrine falcon, Falco peregrinus
(3) (5) (6). The white cheeks contrast with dark eye stripes and a long, dark 'moustache' below the eye, and the eye ring is bright yellow (3) (5). The body is quite slender, with a long, barred tail and long, relatively blunt-ended wings that are dark at the tips (3). The female lanner falcon is usually larger, darker and more patterned than the male, while juveniles are much browner in colour, with heavily streaked underparts, pale blue-grey facial skin, and a duller crown (2) (3) (5). The lanner falcon shows considerable regional variation in size, colouration and degree of spotting and barring, with five subspecies currently recognised (2) (3) (7). The species is usually fairly silent, but at its breeding sites may give a variety of screams and cackling calls (3) (5) (6).