It is similarly used to the Cobra s hood. When a predator nears, the Cockatoo inflates his crest and his head looks larger, often frightening off the predator. A Cockatoo s crest is also thought to be inflatable because it is attractive to a female during the mating season. When a male dances, he lifts it and shows it off much like a Peacock uses its tail and shows it off to a female. Often during mating rituals the male or female will also thrash whatever bush, branch or tree they are on so that the other bird can see how strong they are.
Strong birds make strong young, hence keeping the species alive.
Cockatoos have different dialects in different flocks. Birds in flocks miles away have different languages, just as humans do in different countries. This helps the bird identify with its flock and its genaeology. Cockatoos use tools. Cockatoos can be seen clipping small sticks of wood and then scratching various bodyparts with these pieces, much like we would use a backscratcher.