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 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 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, namely in Southeast Asia.

धनेश एक पक्षी प्रजाति है जिनकी चोंच लंबी और नीचे की ओर घूमी होती है और अमूमन ऊपर वाली चोंच के ऊपर लंबा उभार होता है जिसकी वजह से इसका अंग्रेज़ी नाम Hornbill पड़ा है क्योंकि अंग्रेज़ों ने इस उभार को सींग का दर्ज़ा दिया था। भारत में इसकी ९ जातियाँ पाई जाती हैं।