Hornbills are birds found in tropical and subtropical Africa, Asia and Melanesia  of the family Bucerotidae. They are characterized by a long, down-curved bill which is frequently brightly coloured and sometimes has a horny casque on the upper mandible. Hornbills have a two-lobed kidney. They are the only birds in which the first and second neck vertebrae (the atlas and axis  respectively) are fused together; this probably provides a more stable platform for carrying the bill.[1] The family is omnivorous, feeding on fruit and small animals. They are monogamous breeders nesting in natural cavities in trees and sometimes cliffs. A number of mainly insular  species of hornbill with small ranges are threatened with extinction, mainly in Southeast Asia.