Blyth's hornbill (Rhyticeros plicatus), also known as the Papuan hornbill, is a large hornbill inhabiting the forest canopy in Wallacea and Melanesia. Its local name in Tok Pisin is kokomo.
Previously, this hornbill was placed in the genus Aceros. It has often been lumped with the plain-pouched hornbill (R. subruficollis), and sometimes considered to include the Narcondam hornbill (R. narcondami) and the wreathed hornbill (R. undulatus) as subspecies.
Up to 91 cm in length, the adult male has mainly black plumage with a golden or orange-buff head, white throat and a white tail. Its irises are reddish brown, and the eye is surrounded by naked pale blue skin. The female is a smaller, mainly black bird with a white throat and tail. Both sexes have a very large horn-coloured bill and casque. Young birds of both sexes resemble the male. Adults have up to eight folds on the pale casque, depending on age, while young birds have none.
In flight the sound of its wings is loud and distinctive, a rushing noise that has been compared to the sound of steam escaping from a steam locomotive. It has a range of far-reaching, guttural grunting and laughing calls.