The Great hornbill is a large colorful bird found in the Indian subcontinent and Southeast Asia. Its impressive size and color have made it important in many tribal cultures and rituals. Female Great hornbills are smaller than males and have bluish-white instead of red eyes, although the orbital skin is pinkish. Like other hornbills, they have prominent "eyelashes". The most distinctive feature of the hornbill is the bright yellow and black casque on top of its massive bill. The back of the casque is reddish in females, while the underside of the front and back of the casque is black in males. The commissure of the beak is black and has a serrated edge that becomes worn with age.
Great hornbills are found in India, Bhutan, Nepal, Mainland Southeast Asia, Indonesian Island of Sumatra and Northeastern region of India. In the subcontinent, they are found in the Western Ghats and in the forests along the Himalayas. Their distribution extends into Thailand, Burma, Malaya, and Sumatra. A small feral population is found in Singapore. Great hornbills inhabit moist dense old-growth (unlogged) forests in hilly regions.
Great hornbills are social birds that live in small groups of 2-40 individuals. They are usually seen in small parties, with larger groups sometimes aggregating at fruit trees. These birds are active during the day and when the night comes, they gather in large communal roosts on the highest branches with little foliage. Great hornbills mainly forage along branches, moving along by hopping, feeding on fruits and looking for insects, nestling birds, and small lizards, tearing up bark and examining them. Prey is caught, tossed in the air and swallowed. In one day Great hornbills can visit several fruiting trees and travel long distances to feed. These are very loud and vocal birds; when communicating with each other within communal roosts, they produce deep, hoarse grunts, roars, and barks.
Great hornbills are monogamous and form long-lasting pair bonds. During the breeding season that takes place from January to April, these birds become very vocal. They make loud duets, beginning with a loud "kok" given about once a second by the male, to which the female joins in. The pair then calls in unison, turning into a rapid mixture of roars and barks. The female builds a nest in the hollow of a large tree trunk, sealing the opening with a plaster made up mainly of feces. She remains imprisoned there, relying on the male to bring her food, until the chicks are half developed. During this period the female undergoes a complete molt. The clutch consists of one or two eggs, which she incubates for 38-40 days. The chicks are altricial; they are hatched helpless, have no feathers and appear very plump. The female usually leaves the nest before the young fledge and seals the entrance again. Both parents continue to feed their offspring until they fledge 72-96 days after hatching and become fully independent.
Great hornbills are threatened by habitat loss and hunting. In Southeast Asia, these birds are frequently shot at by poachers who mistake the species for the highly sought-after Helmeted hornbill. Tribal peoples threaten these magnificent birds by hunting for their various parts. The beaks and head are used in charms and the flesh is believed to be medicinal. Young birds are considered a delicacy. Tribesmen in parts of northeastern India and Borneo use the feathers for head-dresses, and the skulls are often worn as decorations. The Sema Nagas consider the flesh unfit for eating, believing that it produces sores on their feet, as in the bird. When dancing with the feathers of the hornbill, they avoid eating vegetables, as doing so is also believed to produce the same sores on the feet.
According to the IUCN Red List, the total Great hornbill population size is approximately 20,000-49,999 individuals, roughly equating to 13,000-27,000 mature individuals. Currently, this species is classified as Vulnerable (VU) and its numbers today are decreasing.
Great hornbills feed mainly on fruit and are important dispersers of many forest tree species. They also control populations of small mammals, insects and reptiles they occasionally consume in their diet.