The Black-headed Ibis is a large waterbird found in South and Southeast Asia, with adults measuring 65–76 cm in length. It has striking white plumage contrasted by a bare black neck and head, along with a down-curved black beak. During the breeding season, the tail feathers become jet black and the bare patches under the wings turn a vivid blood-red. Some breeding adults also develop a bluish tint on the head, or very occasionally, a pink or bright red patch behind the neck. Additionally, breeding adults might show tufts of white feathers behind the neck and, rarely, a yellowish coloration on the breast and back. Males and females look alike, but juveniles can be distinguished from adults by their greyish neck feathers and speckled brown-grey wings and back. Like storks and spoonbills, the Black-headed Ibis lacks a true voice-producing mechanism and is generally silent, except for ventriloquial grunts made by pairs at the nest.