Hornbills in the
genus Buceros include some of the largest arboreal hornbills in the world, with the largest being the
great hornbill. All the hornbills in this genus have a large and hollow bony
casque on their upper beak that can be useful to scientists and bird watchers to recognise their age, sex and species. Their wingspan can be up to 1.8 meters (6 foot) and they have the largest wingspan out of all the hornbills. ==Taxonomy==