The Sulphur-crested Cockatoo (Cacatua galerita) with their overall white plumage, lemon-yellow crest and pale yellow on the underside of the wings, cannot be missed when seeing them in the wild, especially with their loud distinctive raucous calls.
Their crest is a form of communication by the Sulphur-crested Cockatoos. When raised, the crest forms part of their mating rituals, with the male bobbing and strutting motion. This ritual can often be following by mutual touching and preening, with the possibility of mating.
The display of the crest can also indicate defence and posturing (sometimes seen among fellow flock members). A raised crest can also indicate curiosity, excitement, fear and a warning.
A lowered crest is often see as being calm, relaxed and friendly, especially when in company with its mate and during foraging.