In the wild: Great hornbills primarily (70%) eat fat-rich and sugar-rich fruits, but they also feed on small mammals, birds, eggs, amphibians, reptiles and insects. Like many other hornbills, great hornbills have prominent eyelashes on their upper eyelids.As a result, their flight is often noisy and produces a characteristic “whooshing” sound. They lack the short feathers under the wing (underwing coverts) that cover the bases of the primary and secondary flight feathers in other birds.The back of the casque is reddish in females and the underside of the front and back of the casque is black in males. Males and females have identical plumages, but the female is smaller and has a bluish-white iris, while the male’s is red.When viewed from the front the casque is U-shaped, with two ridges along the sides that form points in the front and give the species its Latin name bicornis, meaning two-horned. The most conspicuous feature of the great hornbill is its casque, a hollow structure located on top of the massive bill.A preen gland near the tail secretes tinted oil, spread by the bird during grooming, which may give the bill, neck, tail and wing feathers a color varying from yellow to red. The body, head and wings are mostly black the abdomen and neck are white. The great hornbill is one of the largest hornbills, weighing on average 3 kg (6.6 pounds) and ranging in length from 95 to 120 cm (37.4 to 47.24 in.) with a wingspan of 151 to 178 cm (59 to 70 inches).This species never needs to drink but obtains the water it needs from its diet.Pairs use duets as part of courtship, and the birds call loudly and frequently within their large, communal night roosts. It may also ensure the male’s fidelity to the nest, female and young. The sealing of the nest by the female is thought to have evolved as a predator deterrent.The first two cervical (neck) vertebrae are fused to help support the birds’ large bills.The size and color are also an indication of the age of the bird. It may serve to attract females, to dominate other males, or to serve as a resonance chamber that amplifies the sounds the birds make. The species’ most striking adaptation is the hollow casque, but its function is not precisely known.Fledgling: nest seal is broken and chicks are ready to leave nest cavity may take a few hours to two weeks in clutches with more chicks.The nest entrance is resealed until the chick has grown all its feathers and ready to fly. Nesting: female leaves the nest cavity to help the male forage.Egg incubation: takes nearly six weeks in oriental pied hornbills this stage takes four weeks.Pre-laying: the first egg is laid and the female seals herself to incubate lasts one week.Pre-nesting: mating and selecting nest cavity before the female seals itself lasts one to three weeks.Hornbill nesting period comprises five stages (Poonswad 1993): These differences may be influenced by regional variations. For example, the wreathed hornbill incubates its eggs for 40 days, rhinoceros hornbill 37-46 days, and the helmeted hornbill takes the longest with 150 days. For small hornbills, incubation is 25 days but may take up to 150 days for larger species. Incubation period varies among hornbill species. A number of hornbill species molts at the start of the incubation process, and these feathers will regrow when the female leaves the nest. The female then sheds its feathers to incubate the eggs. Only a small slit remains to allow her mate or other group members to pass through food and discard droppings. Its entrance is sealed by a plaster of dirt, mud, bits of food and droppings to protect her egg from predators and threats from outside of the nest. For example, hornbills in Sulawesi begin to breed in the end of the rainy season.ĭuring incubation, the female hornbill seals herself inside the tree cavity. In addition, breeding is also influenced by seasons, weather and food availability. This condition leads to more intensive competition for nests and affects the breeding cycle. Therefore, an ideal nest cavity may be used repeatedly by the same or different species. For example, the helmeted hornbill requires a stump or large branch by the entrance to perch on when passing food through into the nest.ĭue to high level of destruction of tree and tree hollow, the number of adequate hollows is limited. There are species with specific requirements. Usually hornbills select trees at least 45 cm in diameter with a cavity 20-50 m above the ground. All hornbill species in Asia nest in naturally formed tree hollows, whether broken-off trunks or the abandoned nests of other animals and followed by a weathering process. In the wild, hornbills depend entirely on forest conditions.
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