The yellow-crested cockatoo (Cacatua sulphurea) also known as the lesser sulphur-crested cockatoo, is a medium-sized (about 34-cm-long) cockatoo with white plumage, bluish-white bare orbital skin, grey feet, a black bill, and a retractile yellow or orange crest. The sexes are similar. The yellow-crested cockatoo is found in wooded and cultivated areas of East Timor and Indonesia's islands of Sulawesi and the Lesser Sundas. It is easily confused with the larger and more common sulphur-crested cockatoo, which has a more easterly distribution 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, which is a subspecies of the yellow-crested cockatoo, is similar, but its crest is clearly orange. The yellow-crested cockatoo's diet consists mainly of seeds, buds, fruits, nuts, and herbaceous plants. Taxonomy In the 18th century yellow-crested cockatoos was imported into Europe as pets and these birds were described by various naturalists. In 1738 English naturalist Eleazar Albin included a discription and illustration of the "Cockatoo or White crested parrot" in his A Natural History of Birds based on a bird displayed at "The Tiger" tavern on Tower Hill in London. In 1760 the French zoologist Mathurin Jacques Brisson included "Le Kakatoes à hupe jaune" in his Onithologie based on a live bird that he had seen in Paris. Then in 1764 George Edwards included the "Lesser white cockatoo with a yellow crest" in his Gleanings of natural history from a pet bird kept at a home in Essex, and in 1779 French polymath Comte de Buffon included the bird in his Histoire Naturelle des Oiseaux. When the German naturalist Johann Friedrich Gmelin revised and expanded Carl Linnaeus's Systema Naturae in 1788 he included the yellow-crested cockatoo based on the accounts by earlier naturalists. He placed it with the parrots in the genus Psittacus and coined the binomial name Psittacus sulphureus. The type locality is the island of Sulawesi, Indonesia. The yellow-crested cockatoo in now one of 11 species placed in the genus Cacatua that was introduced in 1817 by Louis Jean Pierre Vieillot. According to the International Ornithological Congress, 6 subspecies are recognized: C. s. sulphurea (nominate subspecies) (Gmelin, JF, 1788) – Sulawesi and nearby smaller islands C. s. abbotti (Abbott's yellow-crested cockatoo) (Oberholser, 1917) – Masalembu Islands C. s. djampeana Hartert, E, 1897