Classification and Range
Hornbills are classified in the order Coraciiformes, which includes kingfishers, todies, motmots, bee-eaters, rollers, hoopoes and other related species. The 54 species of hornbills are further classified into the family Bucerotidae. There are two subspecies of wrinkled hornbills: A. c. corrugatus and A. c. megistus.
The wrinkled hornbill ranges from southern Thailand through Peninsular Malaysia, and the islands of Sumatra and Borneo.
Wrinkled hornbills inhabit lowland primary evergreen forest. As with other hornbills, they are nomadic, covering large areas between foraging areas and roosts.
They occasionally range up to 5,900 feet (1,798 m) in elevation. Radio-telemetry studies have shown that red-knobbed hornbills may cover as much as 23 miles (37 km) per day, passing through degraded habitat in search of fruiting.
The adult male's crown, back of neck, body and wings are black. Its face and front of neck are whitish-yellow, and the tail is white with a broad, black base. The male's bill is yellow with a red-brown base and ridges across the lower mandible. The bill features a deep-red, tall, wrinkled ridge (also called the casque ridge) on the upper mandible near the eyes. The skin around the male's eyes and the inflatable, bare throat skin are pale yellow. Eyes are red, while legs and feet are blue-gray.
The adult female is smaller than the male, with similar black coloring on the head, face and neck. The female's casque has a low profile and the bill is pale yellow with orange at the base. In contrast to the male, the female's facial skin is blue, her eyes are brown, while the legs and feet are blue-gray.
Both sexes of immature wrinkled hornbills have plumage like the adult male. However, their casque ridge is undeveloped and the bill is pale yellow with orange at the base. Juveniles have pale yellow facial skin, yellow-colored eyes with a brown tinge, and blue-gray legs and feet. Immature females molt into their adult face and neck colors at approximately 1 year of age. The juvenile male's plumage remains the same.
Life expectancy in the wild could be approximately 20-30 years. Researchers need information from long-term banding studies to accurately know life expectancy.
Historical records of wrinkled hornbills in captivity provided misleading information, as husbandry issues were underdeveloped and birds died after just a few years. Presently, the oldest living bird in captivity is a wild-caught male that a zoo acquired in 1989. Because it was wild-caught, its exact age is unknown. Life expectancy in captivity probably exceeds that of wild birds. With improved husbandry, more information on longevity will become available on captive-hatched birds.
In the wild:Various fruits (especially figs) are the major part of their diet. Wrinkled hornbills also eat small vertebrates and invertebrates as a small part of their diet.
At the zoo:Apples, papayas, bananas, grapes, blueberries, pear, melon and cooked yams. Some wrinkled hornbills also get juvenile mice twice weekly.
Wrinkled hornbills probably reach sexual maturity at 5-6 years. In Thailand, the breeding season normally occurs from January to June. North American captive births result in hatchings between February and August. If the first clutch fails, the birds will re-nest and try again.
The birds find a natural cavity (caused by lightning strikes, natural decay, etc.) in a large tree and the female seals herself inside. She creates a mixture of feces, food, and feathers into a clay-like substance to seal off the enclosure. A narrow vertical slit in this hard wall provides space for the female to defecate and the male to regurgitate food to the female (and nestlings). She remains inside the nest, incubating two to three white eggs for approximately 30 days. During incubation, the female depends entirely on the male to provide her with food. After hatching, the female remains in the nest, brooding the chicks for another 65-73 days.
The chicks emerge from the nest with the female, or a few days after she has exited the nest cavity. After confinement inside the cramped nest for about 10 weeks, the fledglings are not strong flyers. It takes a day or two of exercising their muscles to enable fledglings to keep up with their parents. Parents continue to feed the juveniles as they forage together in the forests.
In the tropics, food resources vary with space and time. Not all trees provide fruit during the same period of time and fruiting trees often grow far apart. During the non-breeding season, up to 50 hornbills may feed together in the same tree. Eventually, juveniles begin eating on their own. Adults return to the nest in the next breeding season, leaving immature and unpaired birds to roam among fruiting trees.
Toucan or Hornbill?
While toucans and hornbills share many physical characteristics, they are two completely different families of birds. Many people look at hornbills and immediately call them "the Fruit Loops toucan." This confusion is understandable. Both groups of birds have long, sometimes colorful bills. They both nest in cavities in tropical regions, and feed predominantly on fruits. However, this is where the similarities end.
Toucans live only in Central and South America; hornbills live only in Africa and Asia. Toucans are more closely related to woodpeckers, while hornbills are more closely related to kingfishers. The similar appearance of toucans and hornbills is an excellent example of a phenomenon called convergent evolution. This theory hypothesizes that two or more different species from different families and geographically separated locations have adapted similarly to fit an available niche in nature.
An Impenetrable Bond
Because the female depends so much on the male to provide (food) for her and the nestlings, courtship occurs throughout the year to build and maintain strong pair bonds. The male and female invest much time developing this bond, so it is to their advantage to remain together year after year, returning to the same nest site to breed and raise their young.
Location at the Zoo
Wrinkled hornbills are on exhibit in the Conservation Aviary in the Temperate Forest. The Temperate Forest also includes the Family Farm, Bug World, Wetlands and Asian Cranes. Other birds on exhibit in the Conservation Aviary include: various pheasant species, curassows and trumpeters from South America, and several softbills (jays, laughing thrushes, turacos, whistling thrushes, birds of paradise and mynahs).
Wrinkled hornbills are not an endangered species. However, they are considered endangered in southern Thailand, since this area is the extreme northern part of their range. Throughout the rest of their range, they are more common, but listed as near threatened. Other species of hornbills are not so fortunate, as at least four species are listed as endangered.
Years ago, poaching threatened wrinkled hornbill survival rates, as villagers raided nests to sell nestlings for the pet trade. Today, the biggest threat to this hornbill is logging, which results in loss of habitat. Excessive logging removes the required large trees with naturally occurring cavities. To fully assess the status of wrinkled hornbills, researchers need more studies to determine if the population is stable or declining.
Hornbills are important because they help disperse seeds throughout the forest. They regurgitate larger seeds, and pass smaller seeds through their feces. It may be that forests need hornbills as much as hornbills need forests. The presence of nesting hornbills is a sign of a healthy Asian tropical rain forest.
Woodland Park Zoo is Helping - With Your Support!
Each in-situ project supported by Woodland Park Zoo (WPZ) aims to provide a broad, holistic approach to conservation, encompassing research, education, habitat and species preservation. This includes comprehensive, cooperative strategies to link the needs of animals with the people who share their ecosystems.
Since 1999, WPZ staff, volunteers, members and friends have adopted more than 254 hornbill nests in southern Thailand. This is a win-win situation for all involved: the hornbills get protected, the researchers obtain data, and the villagers get much needed cash to improve their lives.
An outcome of the above program was the construction and staffing of the Conservation-Education Center in Tapoh Village, Narathiwat Province in southern Thailand. WPZ has supported this Education Center since 2001.
How You Can Help!
The effort to save animal species requires cooperation and support at the international, national, regional and individual levels. You can help in this cause. Join and become active in WPZ and other conservation organizations of your choice. Let your elected representatives know your views on protecting endangered species and wild habitats. Please do not buy products made from wild animal parts.
Contact the WPZ at 206.548.2500 or visit the Hornbill Nest Adoption page to find out how you can adopt a hornbill nest. One hundred percent of the adoption money (at a price of $150 per nest per year) goes directly to the villagers who guard nests in neighboring Budo-Sungai Padi National Park. Along with protecting the birds and nest sites, they collect valuable data for the Hornbill Research Foundation. At the end of the breeding season, nest results are sent to each adopter. Included with these results are colored photos of the birds at the nest and the local villager who protected it.
Sources and Suggested Reading
del Hoyo, J., Elliot, A. & Sargatal, J. eds. 2001. Handbook of the Birds of the World, Volume 6. Mousebirds to Hornbills. Lynx Edicions, Barcelona, Spain. 589 p.
Kemp, A.C. 1995. The Hornbills. Oxford University Press, Oxford, UK. 302 p.
Kowalczyk, E. 2006. North American Regional Studbook: Genus Aceros. (unpublished but distributed to ISIS and AZA facilities). 114 p.
Lindholm, J.H. 1999. The wrinkled hornbill, Aceros corrugatus. In: The AFA Watchbird XXVI (5): 55-62.
Poonswad, P. 1993. Forest flagships. In: World Birdwatch 15(3): 14-17.
Taxonomic Advisory Group
Hornbill Research Foundation