The Cockatoo or Cocky is one of the most well known of the Australian Birds. The plumage is white, while the underwing and -tail are tinged yellow. The expressive crest is yellow. It is similar in appearance to the three species of corellas found in Australia. However, corellas are smaller and lack the prominent yellow crest.

Their distinctive raucous call can be very loud and is adapted to travel through the forest environments in which they live, including tropical and subtropical rainforests. These birds are naturally curious, as well as very intelligent. They have adapted very well to European settlement in Australia and live in many urban areas. These birds can live upwards of 70 years in captivity, although they only live to about 20–40 years in the wild.

The Sulphur-crested Cockatoo is a seasonal breeder. In southern Australia the breeding season is from August to January, whereas in northern Australia the season is from May to September. The nest is a bed of wood chips in a hollow in a tree. Like many other parrots it competes with others of its species and with other species on nesting sites. Two to three eggs are laid and incubation lasts between 25–27 days. Both parents incubate the eggs and raise the nestlings. The nestling period is between 9 to 12 weeks, and the young fledglings remain with their parents for a number of months.

Species that feed on the ground are very vulnerable to predator attack. The Cockatoo has evolved a behavioural adaptation to protect against this: whenever there is a flock on the ground, there is at least one high up in a tree (usually a dead tree), keeping guard. This is so well-known that it has even entered Australian slang: a person keeping guard for sudden police raids on illegal gambling gatherings is referred to as a Cockatoo or Cocky for short.