Black Kite Bird is shorter and somewhat smaller than the Red Kite, it is comparable in size to a female Marsh Harrier. Apart from plumage differences from that species, the Black Kite always cruises with the wings bowed and hanging heavy, as opposed to holding them up in a shallow 'V'. Black Kite Bird is earth-brown overall, the head a little greyer, and it shows a paler brown band on the upperwing coverts. The underwing is a fairly uniform brown, with an indistinct paler panel on the inner primaries. The belly and vent are rufous-brown, and the tail is grey-brown and with a shallower fork (or notch) than Red Kite. The tail appears triangular or square-ended when spread, usually when soaring or foraging at slow speeds, when it twists it around like a rudder.
Black Kite Bird is similar to Red Kite, although much less disturbed by the activities of man. Black Kite bird favours partly wooded areas and open country, nesting in a tree, and has a strong affinity for wetland habitats, where it scavenges along the margins for fish and other carrion. It is very adaptable and will eat almost any animal food, and also indulges in piracy of other birds' prey. It can be very sociable and forms large gatherings where carrion is plentiful, such as around rubbish tips. It is more frequently found around cultivated areas and human habitation than Red Kite.
Black Kite Bird is similar to Red Kite, but more vocal than that species. Black Kite bird has a rather petulant, urgent-sounding, shrill whinnying "peeeeh-ee-ee-ee-ee" or "aeow-rr'rr'rr", which is variable in length and intensity. It is given more frequently in the breeding season, by both sexes, and both in flight and at rest. The first syllable is emphasized, and the whinnying becomes more staccato when the bird is excited, as in "pew-e'e'e'e'e". It also gives a mewing whistle, a whingeing "peeeee-eeeee...", with this sound sometimes preceding the main call type.