Characteristic features of parrots include a strong, curved bill, an upright stance, strong legs, and clawed feet. Many parrots are vividly coloured, and some are multi-coloured. The plumage of cockatoos ranges from mostly white to mostly black, with a mobile crest of feathers on the tops of their heads. They form the most variably sized bird order in terms of length.
The most important components of most parrots' diets are seeds, nuts, fruit, buds and other plant material. A few species sometimes eat animals and carrion, and soft fruits. Almost all parrots nest in tree hollow, and lay white eggs from which hatch helpless young.