The hornbills (Bucerotidae) are a family of bird found in tropical and subtropical Africa, Asia and Melanesia. They are characterized by a long, down-curved bill which is frequently brightly colored and sometimes has a casque on the upper mandible. Both the common Englishand the scientific name of the family refer to the shape of the bill, “buceros” being “cow horn” in Greek. 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. The family is omnivorous, feeding on fruit and small animals. They are monogamousbreeders nesting in natural cavities in trees and sometimes cliffs. A number of species of hornbill are threatened with extinction, mostly insular species with small ranges.