The Yellow-crested Cockatoo, Cacatua sulphurea, also known as the Lesser Sulphur-crested Cockatoo, is a medium-sized (approximately 35 cm long) cockatoo with white plumage, bluish-white bare orbital skin, grey feet, a black bill, and a retractile yellow crest. The sexes are similar.
C.s. sulphurea: both adults white plumage with yellow at bases of feathers of head and underparts; bright yellow crest and ear coverts. Eye ring soft white. Eye dark brown in male, brown/red in female. C.s. parvula: both adults as in sulphurea, but yellow ear coverts paler and feather bases less yellow where mentioned. C.s. abbotti: both adults as in parvula but larger in size. C.s. citrinocristata: both adults crest and ear coverts golden orange.
C.s. sulphurea: as in adult, but with pale grey eye. C.s. parvula: as in adult. C.s. abbotti: as in adult. C.s. citrinocristata: as in adult.
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.
|Population estimate||Population trend||Range estimate (breeding/resident)||Country endemic?|
Range & population Cacatua sulphurea is endemic to Timor-Leste and
Indonesia, where it was formerly common throughout Nusa Tenggara (from Bali to Timor), on Sulawesi and its satellite islands, and the Masalembu Islands (in the Java Sea). It has undergone a dramatic decline, particularly in the last quarter of the 20th century, such that it is now extinct on many islands and close to extinction on most others. Sumba appears to support the largest remaining population, tentatively estimated (in 1992) at c.3,200 birds (but declining by perhaps 500 birds annually, with just 10% of the island still forested in 34 fragments2), with other significant (but considerably smaller) populations on Komodo (c.500 individuals), Sulawesi, Buton, Moyo and Timor-Leste1. Tiny populations of just a few individuals also exist in the Tukangbesi Islands, on Oroho Island (a satellite of Wangi Wangi Island) and on Lintea Selatan (a satellite of Tomea Island)10. The Komodo population alone (where poaching is virtually absent) declined by an estimated 60% between 2000-20055. Its current status on several small islands is unclear, but surveys of Masakambing on the Masalembu Islands in 2008 found only ten individuals remaining of race abbotti9. A feral population of several hundred birds exists in Hong Kong.
Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.
Ecology: It inhabits forest (including evergreen, moist deciduous, monsoon and semi-evergreen), forest edge, scrub and agriculture up to 500 m on Sulawesi, and 800 m (sometimes 1,500 m) in Nusa Tenggara. On at least some islands (e.g. Sumba), it appears heavily dependent on closed-canopy primary forest. On others, it survives despite the total clearance of original vegetation, indicating that its habitat requirements are somewhat flexible. Breeding takes place from September to May on Sumba2. It nests in tree cavities with specific requirements.
Threats Its precipitous decline is almost entirely attributable to unsustainable exploitation for internal and international trade. Large-scale logging and conversion of forest to agriculture across its range has exacerbated the decline, and the use of pesticides since around 1989 is a further potential threat. At least formerly, the species was regarded as a crop-pest, and consequently persecuted. High rainfall years appear to limit productivity considerably resulting in very low recruitment. Conversely, rainfall on Komodo has been low in recent years leading to limited availability of water sources. Competition for cavity nest sites with other parrots and owls in large trees (those targeted by logging activities) leads to low productivity2.
Conservation measures underway CITES Appendix I (2005). A cooperative recovery plan has been developed and adopted. Populations occur in several protected areas, the most important being Rawa Aopa Watumohai and Caraente National Parks (on Sulawesi) which supports up to 100 individuals6, Suaka Margasatwa Nature Reserve on Pulau Moyo, Komodo National Park and two national parks on Sumba: Manupeu-Tanahdaru and Laiwangi-Wanggameti. The declared Nini Konis Santana National Park in Timor holds an estimated 100 birds1. Moratoria on international trade have been effective at allowing several subpopulations on Sumba to increase in number between 1992 and 2002, although densities remained below those typical of other cockatoo species4
Conservation measures proposed Conduct further surveys to identify the most appropriate areas for conservation action and to periodically monitor key populations by repeating surveys conducted 8-10 years ago. Conduct ecological research to clarify options for its management and conservation. Provide support for relevant protected areas and conservation initiatives within its range and protect nest-trees where possible. Strengthen control and monitoring of trade. Improve law enforcement in designated protected areas. Promote widespread community-based conservation initiatives. Recommendations made specifically for the protection of the species in Komodo National Park were to conduct annual monitoring, maintain regular patrols, raise awareness in local communities and study human activities and impacts within the park3,5. Additional targets should be to study the abundance and distribution of nest holes and water sources. Providing artificial water sources near nest locations, i.e water ponds, is essential for Yellow-crested Cockatoo on Komodo Island.
References BirdLife International (2001). 1. Trainor et al. (undated). 2. Walker et al. (2005). 3. Benstead (2006). 4. Cahill et al. (2006). 5. Imansyah et al. (2005). 6. Nandika (2006). 7. Agista and Rubyanto (2001). 8. Imansyah et al. (2008). 9. Anon (2008). 10. D. Kelly in litt. (2009).