The greater flameback is a large
woodpecker, at 33 cm in length. It is of typical woodpecker shape, and has an erect
crest and a long neck. Coloration is highly variable between
subspecies; it always has unmarked golden-yellow to dark brown back and wings. The rump is red and the tail is black. The underparts are white with dark markings (chevrons, stripes, or bands), or light brown. The head is whitish with a black pattern, or it is yellow, brown, or red. The straight-pointed bill is longer than the head, and the legs have four-toed
zygodactyl feet (two toes pointing forward, two backward) and are lead-grey in color. The eyes'
irises are whitish to yellow. The adult male greater flameback always has a red crown. Females have a crown color varying between subspecies, such as black spotted with white, yellow, or brown with lighter dots. Young birds are like the females, but duller, with brown irises.
Similar species White-and-black-headed greater flameback subspecies resemble some of the three-toed
Dinopium flamebacks, but are not particularly closely related. Unlike the
black-rumped flameback (
D. benghalense) and the
common flameback (
D. javanense), the greater flameback's dark moustache stripes are divided by white (making them inconspicuous at a distance); except in
C. stricklandi, their hindneck is white (not black), and even in the Sri Lankan birds, the dark colour does not extend to between the shoulders as it does in
Dinopium; consequently, when seen from behind, the black-and-white-headed greater flamebacks outside Sri Lanka show a white neck bordered with black on the sides, while the
Dinopium species have a black neck and upper back, with thin, white borders to the neck. Those flamebacks are also smaller (though this is only reliable in direct comparison), have a bill that is shorter than the head, and dark irises. ==Behaviour and ecology==