White-crowned hornbill  (Aceros comatus)

The most noticeable feature of this fantastically bizarre looking bird is its white crown feathers which erect in a spiky crest. The white-crowned hornbill also possesses an ornamental casque on top if its bill, characteristic of many hornbills. The blackish casque is hollow and serves no function, but is believed to be the result of sexual selection. The head, neck, breast, gradual tail and tips of the wing feathers are white, while the rest of the plumage is black, with a metallic sheen to the upperparts. The large bill is black with a greenish-yellow wash at the base. The bare skin surrounding the eye and on the throat is a striking blue, and the eyes are pale yellow. Females are smaller than males, and are also distinguished by their black neck and underparts (2) (4).

Occurs in southern Myanmar, southern Thailand, Peninsular Malaysia, Sumatra and Borneo. A population has also recently been discovered in Cambodia (4).

The white-crowned hornbill occurs in primary evergreen forest, favouring areas of thick tangled growth, and venturing into rubber, oil-palm and fruit plantations adjacent to forest and selectively logged areas. It is usually found below 900 meters, but has been recorded up to 1,680 meters (2) (4).

Despites its distinctive appearance, the white-crowned hornbill has been described as an unobtrusive bird that remains beneath the forest canopy, and so is most often heard, or spotted as it flies across gaps in the forest in small groups (2). The diet consists primarily of animals, such as birds, lizards, snakes, insects, arthropods and larvae which it finds amongst bark, stems and debris from logging, but it also feeds on a variety of fruits (2) (4). The white-crowned hornbill undertakes short, ‘floppy' flights between forest patches, where it then hops and climbs amongst the dense undergrowth looking for food.

The white-crowned hornbill is a territorial bird, and assumes a distinct threat posture when intimidated; it faces it opponent with its wings open, tail spread and bill lowered. Territories are occupied by a group of three to eight individuals, usually consisting of one dominant breeding pair, one to three helpers and a number of juveniles (2). The breeding pair is monogamous, with a co-operative breeding system, in which other adults and young in the group assist with the feeding of the breeding female and the chicks (5). The nest is situated in natural holes in logged or unlogged forest (2), and like other hornbills, the female seals herself into the tree hole with her own faeces, regurgitated food and mud, leaving only a small opening through which the male passes food. When the chicks fledge, the female and her young leave the nest (5).

The white-crowned hornbill has a large range, but is generally uncommon throughout (4). The destruction of forest habitat is likely to have impacted this species in the past, and will continue to do so in the future (2). However, the white-crowned hornbill can survive at higher elevations where the destruction of forests is not so severe, and thus it is not yet considered to be globally threatened (6),

The white-crowned hornbill is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which means that any trade in this species should be tightly controlled (3). It also occurs within a number of protected areas across its range (4), but at present there are no known specific conservation actions in place for this bird.

For further information on this species see Kemp, A.C. (1995) The Hornbills. Oxford University Press, Oxford.

For further information on the conservation of hornbills in Thailand see the Hornbill Research Foundation:
http://web.utk.edu/~vchimcho/hornbill/index.html

Authenticated (27/07/07) by Dr Pilai Poonswad, Thailand Hornbill Project.
scpps@mahidol.ac.th