The Yellow-crested Cockatoo, Cacatua sulphurea, also known as the Lesser Sulphur-crested Cockatoo, is a medium-sized (up to 35cm long) cockatoo with white plumage, bluish-white bare orbital skin, grey feet, a black bill, and a retractile yellow crest. The sexes are similar.
The Yellow-crested Cockatoo is found in wooded and cultivated areas of Timor-Leste and Indonesia's islands of Bali, Timor, Sulawesi and Lesser Sunda Islands. It is easily confused with the larger and more common Sulphur-crested Cockatoo, which is native to Australia and can be distinguished by the lack of pale yellow coloring on its cheeks (although some sulphur-cresteds develop yellowish patches). Also, the Yellow-crested Cockatoo's crest is a brighter color, closer to orange. The Citron-crested Cockatoo is similar, but its crest is orange.
The Yellow-crested Cockatoo's diet consists mainly of seeds, buds, fruits, nuts and herbaceous plants.
The Yellow-crested Cockatoo nests in tree cavities. The eggs are white and there are usually two in a clutch. The incubation is shared by both parents. The eggs are incubated for about 28 days and the chicks leave the nest about 75 days after hatching.
The Yellow-crested Cockatoo is critically endangered. Numbers have declined dramatically due to illegal trapping for the cage-bird trade. The current population is estimated at less than 10,000. It is listed on Appendix I of CITES.
The subspecies abbotti is found only on the island of Masakambing, one of the Masalembu islands. Its population on this tiny island (about 5 km2 or 1.9 mi2) had fallen to 10 as of June and July 2008. The decline results from trapping and logging, especially of mangrove (Avicennia apiculata) and kapok trees.
There is a feral population of these birds in Hong Kong. They are a common sight in the densely populated Sheung Wan area of the city. The large group has apparently developed from a number of caged birds that have been released into the Hong Kong skies over many years. An often repeated story is that Hong Kong Governor Sir Mark Aitchison Young released Government House's entire bird collection "? including a large number of Yellow-crested Cockatoos "? hours before surrendering Hong Kong to Japanese troops in December 1941.