The sulphur-crested cockatoo (Cacatua galerita) is a relatively large white cockatoo found in wooded habitats in Australia, New Guinea, and some of the islands of Indonesia. They can be locally very numerous, leading to them sometimes being considered pests. A highly intelligent bird, they are well known in aviculture, although they can be demanding pets. Distribution In Australia, sulphur-crested cockatoos can be found widely in the north and east, ranging from the Kimberley to as far south as Tasmania, but avoiding arid inland areas with few trees. They are numerous in suburban habitats in cities such as Adelaide, Melbourne, Canberra, Sydney and Brisbane. Except for highland areas, they occur throughout most of New Guinea and on nearby smaller islands such as Waigeo, Misool and Aru, and various islands in the Cenderawasih Bay and Milne Bay. There are four recognised subspecies: Introduced species Within Australia, sulphur-crested cockatoos of the nominate race have also been introduced to Perth, which is far outside the natural range. Outside Australia, they have been introduced to Singapore, where their numbers have been estimated to be between 500 and 2000. They have also been introduced to Palau and New Zealand. In New Zealand, the introduced populations may number less than 1000. This species has also been recorded as established in Hawaii and from various islands in Wallacea (e.g. Kai Islands and Ambon), but it is unclear if it has managed to become established there. Description Sulphur-crested cockatoos are long, with the Australian subspecies larger than subspecies from New Guinea and nearby islands. The plumage is overall white, while the underwing and -tail are tinged yellow. The expressive crest is yellow. The bill is black, the legs are grey, and the eye-ring is whitish. Males typically have almost black eyes, whereas the females have a more red or brown eye, but this requires optimum viewing conditions to be seen. The differences between the subspecies are subtle. C. g. fitzroyi is similar to the nominate race but lacks the yellow on the ear tufts and has slightly blueish skin around the eye. C. g. eleonora is similar to C. g. fitzroyi but is smaller and has broader feathers in the crest, and C. g. triton is similar to C. g. eleonora except it has a smaller bill. It is similar in appearance to the three species of corellas found in Australia. However, corellas are smaller, lack the prominent yellow