The knobbed hornbill (Aceros cassidix) also known as Sulawesi wrinkled hornbill is a large black hornbill with a yellow bill, white tail feathers, pale blue skin around eye, blackish feet and bare dark blue throat.

The male has rufous/buff face and neck, orange-red eyes, and a high reddish casque on the top of his bill. The female has a black face and neck, a yellow casque, and brownish eyes