Sulphur-crested Cockatoos are large parrots, ranging between 44 – 51 cm in length, with a wingspan of up to 103 cm. The feathers on their neck and head are white with concealed pale yellow. There are also yellow markings underneath their wings which can be seen when flying. Sulphur-crested Cockatoos have a distinctive yellow crest on the back of their head which sticks up when alarmed. They also have a dark black beak. Male and female birds are similar in appearance.