Sunda wrinkled hornbill  (Aceros corrugatus)

The Sunda wrinkled hornbill is classified as Near Threatened (NT) on the IUCN Red List (1) and listed on Appendix II of CITES (4).

The Sunda wrinkled hornbill (Aceros corrugatus) gains its common name from its casque, a prominent bony crest on top of its large bill which in this species is wrinkled and ridged (5).

The male and female Sunda wrinkled hornbill differ in appearance. The male Sunda wrinkled hornbill has a deep yellow bill with a red base, and a wrinkled red or orange casque (2) (5). The male’s eyes are surrounded by a rim of light blue skin, while the sides of the head, upper breast and tail are white, and the neck is bright yellow. The body, wings and tail tip of the male are black with a metallic green sheen (2) (3). The female is smaller than the male and completely black, except for a yellow bill and casque, and a distinguishing bright blue neck (2). The female also has a smaller casque than the male (5).

The juvenile Sunda wrinkled hornbill looks similar to the adult male, but lacks any red colour and has a small, pale yellow bill that lacks a casque (2).

The calls of the Sunda wrinkled hornbill consists of one to three coughing notes, described as “sok, sok sok” or “kowwow”. The flapping wings produce an extremely loud rushing sound (3). 

The Sunda wrinkled hornbill is found in southeast Asia, where it is native to the Sundaic lowlands of Thailand, Brunei, Sumatra, Indonesia and Malaysia (6). It is regionally extinct from Singapore, where it was last seen in 1941 (3).

The Sunda wrinkled hornbill inhabits primary, evergreen and swamp forests in lowland areas. This species is not found in secondary forests that have been disturbed in any way. It can be found up to elevations of 1,000 metres, but is most commonly seen below 30 metres (2) (6).

The diet of the Sunda wrinkled hornbill consists mainly of fruit, in particular drupes and figs (2) (3). The Sunda wrinkled hornbill can often be found in pairs when feeding, but has been known to occur in groups of up to 30 birds in large fruit trees. The Sunda wrinkled hornbill is not aggressive or territorial (3).

There is little information about the breeding habits of the Sunda wrinkled hornbill in the wild, although it is reported to breed during the rainy season, between December and January (5). In captivity, the male has been observed to chase and feed the female during courtship (3).

Hornbill species are monogamous. After mating, the female will find a deep hole in a tree to nest in, and seals herself inside the hole with droppings and left over food. The female remains on the nest from egg laying until the chicks fledge with the whole process taking about 111 to 124 days. During this period, the male will make a small hole in the seal to feed the female, and breaks the seal when the female and fledglings emerge (2).

Habitat loss poses the greatest threat to the Sunda wrinkled hornbill. There has been extensive loss of Sundaic lowland forests due to widespread illegal logging, land conversion and forest fires, and the Sunda wrinkled hornbill’s dependence on undisturbed primary forest makes it particularly vulnerable to these threats (6). At higher elevations, deforestation has been less severe, meaning that these populations are less threatened. However, the Sunda wrinkled hornbill is on the verge of extinction in Thailand (7).

There are few specific conservation measures currently in place for the Sunda wrinkled hornbill. However, it is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in this species should be carefully regulated (4).

The population size and the range of the Sunda wrinkled hornbill are likely to be declining as deforestation continues to deplete suitable habitat. This needs to be carefully monitored with frequent population surveys. The protection of remaining lowland forests is also needed to ensure the continued survival of this beautiful hornbill species (6). 

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more about the Sunda wrinkled hornbill:

• BirdLife International - Sunda wrinkled hornbill:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=965
• HonoluluZoo - Sunda wrinkled hornbill:
  http://www.honoluluzoo.org/wrinkled_hornbill.htm