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Yellow-crested Cockatoo Cacatua sulphurea Scientific name definitions

Ian Rowley, Christopher J. Sharpe, Peter F. D. Boesman, and Guy M. Kirwan
Version: 1.2 — Published October 22, 2024
Revision Notes

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Field Identification

ca. 33 cm; 350 g. White cockatoo with long, forward-curving yellow crest feathers, yellow ear coverts, and yellow undersurfaces of wings and tail; bill black; feet gray; eye black in male, red-brown in female; bare periophthalmic skin pale blue. Immature similar to adult, but iris pale gray.

Similar Species

Linear Measurements

Overall length ca. 33 cm (1).

Linear measurements (means and standard deviation, with sample sizes in parentheses), from Collar and Marsden (2).

Wing length Tail length Bill length Crest length Ear patch size
Males
C. s. sulphurea 225 ± 6.43 (n = 20) 113 ± 2.38 (n = 21) 38.3 ± 1.81 (n = 19) 101 ± 4.07 (n = 20) 29.8 ± 3.01 (n = 20)
C. s. abbotti 263 ± 5.82 (n = 6) 138 ± 6.62 (n = 6) 35.1 ± 1.21 (n = 6) 123 ± 4.8 (n = 5) 20.5 ± 4.14 (n = 4)
C. s. occidentalis 220 ± 5.13 (n = 15) 110 ± 5.13 (n = 14) 36.9 ± 0.76 (n = 13) 94.3 ± 5.42 (n = 15) 23.7 ± (n = 15)
C. s. parvula 223 ± 5.5 (n = 4) 121 ± 5.03 (n = 4) 33.5 ± 1.94 (n = 4) 101 ± 6.61 (n = 4) 20.1 ± 0.63 (n = 4)
C. s. djampeana 220 ± 7.34 (n = 6) 111 ± 4.4 (n = 6) 34.1 ± 1.3 (n = 6) 92.5 ± 3.77 (n = 5) 26.6 ± 2.38 (n = 5)
C. s. paulandrewi 221 (n = 3) 112 (n = 3) 33.2 (n = 3) 95.5 (n = 2) 24.0 (n = 2)
Females
C. s. sulphurea 221 ± 6.54 (n = 32) 112 ± 2.1 (n = 32) 35.6 ± 1.79 (n = 30) 98.7 ± 4.55 (n = 31) 28.8 ± 3.07 (n = 28)
C. s. abbotti 260 (n = 2) 146 (n = 2) 33 (n = 2) 117 (n = 2) 15.5 (n = 2)
C. s. occidentalis 213 ± 7.75 (n = 15) 109 ± 4.82 (n = 15) 33.8 ± 1.82 (n = 14) 93.2 ± 6.16 (n = 15) 21 ± 2.3 (n = 13)
C. s. parvula 219 ± 4.42 (n = 7) 120 ± 2.45 (n = 7) 31.1 ± 0.66 (n = 7) 97.4 ± 6.5 (n = 7) 20.7 ± 1.7 (n = 7)
C. s. djampeana 213 ± 5.04 (n = 10) 108 ± 4.11 (n = 10) 30.9 ± 1.66 (n = 10) 90.1 ± 6.4 (n = 10) 23.8 ± 2.67 (n = 9)
C. s. paulandrewi 213 (n = 3) 109 (n = 3) 29.3 (n = 3) 90.7 (n = 3) 20.0 (n = 2)

Mass

350 g (1).

Systematics History

Yellow-crested Cockatoo has often been considered conspecific with Citron-crested Cockatoo (Cacatua citrinocristata) (e.g., 3, 4, 5, 6), but is here split largely on the basis of its distinctive morphology (2, 7, 8, 9). Citron-crested Cockatoo differs from Yellow-crested Cockatoo in its long peachy-orange versus yellow crest, longer tail (2), and different juvenile bill coloration (10).

Geographic Variation

Populations are separated by differences in size (see Measurements), the intensity of yellow on the ear-coverts, and crest color (most recent and detailed review by 2).

Subspecies

Six subspecies currently recognized.


SUBSPECIES

Cacatua sulphurea abbotti Scientific name definitions

Systematics History

Kakatoe parvulus abbotti Oberholser, 1917, Proceedings of the United States National Museum 54:181.—“Solombo Besar Island, Java Sea” [= Masalembu Island]. (11)

The holotype, an adult male collected on 4 December 1907 by William Louis Abbott (1860–1936), is held at the National Museum of Natural History, Smithsonian Institution, Washington, DC (USNM 181453) (12).

Distribution

Masalembu Island (eastern Java Sea) (2, 13).

Identification Summary

C. s. abbotti can be diagnosed from the other taxa by having the longest crest, wings and tail, a mid-sized bill (see Measurements), and at most a small (sometimes obsolete) and brownish ear-covert patch (2).


SUBSPECIES

Cacatua sulphurea sulphurea Scientific name definitions

Systematics History

Psittacus sulphureus J. F. Gmelin, 1788, Systema Naturae, 13th edition, Tome 1, p. 330.—Moluccas. (14)

Gmelin based his name on the prior indication of Brisson; very few of the latter’s bird specimens survive (15) and this species is not among them (16).

Synonym:
Cacatua aequatorialis Temminck, 1849, Coup-d’Oeil Général sur les Possessions Néerlandaises dans l’Inde Archipélagique, Volume 3, p. 405.—Celebes [= Sulawesi]. Known on the basis of two syntypes, both held in the Naturalis Biodiversity Center, Leiden, and collected by Eltio Alegondas Forsten (1811–1843) at Tomini sometime between September 1841 and April 1842, an adult male (RMNH.AVES.87996) and an adult female (RMNH.AVES.87997) (17, 18).

Distribution

Sulawesi, Muna, Butung, Tanahjampea, and adjacent islands (2, 13).

Identification Summary

The nominate subspecies is characterized by having the largest bill (see Measurements), and consistently the largest and richest lemon-yellow ear-covert patch (2).


SUBSPECIES

Cacatua sulphurea djampeana Scientific name definitions

Systematics History

Cacatua sulphurea djampeana E. Hartert, 1897, Novitates Zoologicae 4:164.—“Djampea” [= Tanah Jampea]. (19)

The lectotype, a female collected in December 1895 by Alfred Hart Everett (1848–1898), is held at the American Museum of Natural History, New York (AMNH 619652); designation by Hartert (20); there is also a paralectotype with the same data (AMNH 619653) (21).

This subspecies is sometimes subsumed into nominate sulphurea (5).

Distribution

Islands in the Flores Sea: Tanah Jampea Islands (Kayuadi, Tanah Jampea, Kalao, Kalaotoa, and Madu) and Tukangbesi Islands (Wangiwangi, Tomea, and Binongko) (2, 13).

Identification Summary

In size, C. s. djampeana is like C. s. occidentalis but has a smaller bill (see Measurements), as well as a consistently larger and mostly more colourful ear-covert patch (2).


SUBSPECIES

Cacatua sulphurea paulandrewi Scientific name definitions

Systematics History

Cacatua sulphurea paulandrewi Collar and Marsden, 2014, Forktail 30:26.—Wanci (Wangiwangi Island). (2)

The holotype, a male collected on 3 December 1901 by Heinrich Kühn (1862‒1906), is held at the American Museum of Natural History, New York (AMNH 619651) (2).

Distribution

Endemic to the Tukangbesi Islands, south of Sulawesi (2, 13).

Identification Summary

Diagnosed from C. s. djampeana on the basis of its smaller bill and ear-covert patch (see Measurements), and by the latter’s paler coloration (2).


SUBSPECIES

Cacatua sulphurea occidentalis Scientific name definitions

Systematics History

Cacatua parvula occidentalis E. Hartert, 1898, Novitates Zoologicae 5:120.—Lombok. (22)

The lectotype, a male collected in July 1896 by Alfred Hart Everett (1848–1898), is held at the American Museum of Natural History, New York (AMNH 619657); designation by Hartert (20); there are also five paralectotypes, three males (AMNH 619658‒619660) and two females (AMNH 619661 and AMNH 619662) collected between 1,000 and 5,000 ft. on Lombok by William Doherty (1857–1901) (21).

Subspecies occidentalis is sometimes subsumed into parvula (5).

Distribution

Western and central Lesser Sundas (Lombok, Sumbawa, Komodo, Padar, Rinca, Flores, Pantar, and Alor); probably extirpated on Lombok, and critically rare on Sumbawa and Flores (2, 13).

Identification Summary

C. s. occidentalis has a large bill, but short wings and tail (see Measurements), and a relatively small, usually pale to very pale lemon-yellow ear-covert patch (2).


SUBSPECIES

Cacatua sulphurea parvula Scientific name definitions

Systematics History

Plyctolophus parvulus Bonaparte, 1850, Comptes Rendus Hebdomadaires des séances de l’Académie des sciences 30:139.—no locality. (23)

Bonaparte (23) gave no indication of the number of specimens available to him; an adult female collected at Semao, Timor, Indonesia, sometime between October 1828 and December 1829 by Salomon Müller (1804–1864), held at the Naturalis Biodiversity Center, Leiden (RMNH.AVES.87995) was reported by van den Hoek Ostende et al. (17) to be the holotype, which constitutes a lectotype designation (see 18).

Distribution

Lesser Sundas (Sumbawa to Timor) (2, 13).

Identification Summary

C. s. parvula has the smallest bill and ear-covert patch of any subspecies, but has a longer tail than all except C. s. abbotti (see Measurements), and a relatively small and consistently very pale lemon-yellow ear-covert patch (2).

Related Species

Yellow-crested Cockatoo is presumably closely related to Citron-crested Cockatoo (Cacatua citrinocristata), with which it was formerly considered conspecific; however, the two have not been included together in any molecular phylogenetic study. In two phylogenetic studies that included Yellow-crested Cockatoo, it was found to be sister to Sulphur-crested Cockatoo (Cacatua galerita), with these two species in turn sister to White Cockatoo (Cacatua alba) (24, 25), though support values for relationships within this small clade were not strong (25). Further work is needed to resolve the relationships among these large cockatoos, including Citron-crested Cockatoo.

Hybridization

Not recorded.

Hybrid Records and Media Contributed to eBird

  • Tanimbar Corella x Yellow-crested Cockatoo (hybrid) Cacatua goffiniana x sulphurea

Nomenclature

The recently described subspecies C. s. paulandrewi (2) was named for Paul Andrew (1953–2020), the author of the first checklist of Indonesian birds (26).

Fossil History

Information needed.

Distribution

Sulawesi, including Muna and Buton islands, Masalembu Besar Island, Tukangbesi Islands (Wangiwangi, Tomea, and Binongko) and Selayar Islands (Pulau Kayuadi, Pulau Tanahjampea, Pulau Kalao, Pulau Kalaotoa, and Madu), in Flores Sea, Nusa Tenggara Islands (Lesser Sundas) (Lombok, Sumbawa, Komodo, Padar, Rinca, Flores, Pantar, Alor, Roti, Semau, and Timor).

Introduced Range

Introduced to Hong Kong and Singapore.

Habitat

Woodland and cultivation, but not found inside forests; occurs from sea-level up to 500 m on Sulawesi, and sometimes up to 1200 m elsewhere.

Diet and Foraging

Feeds mainly in trees , taking seeds, nuts, berries, and fruit. Destroys young fruits of Ceiba and Gossampinus, and attacks coconuts.

Vocalizations

Vocal Array

Commonest call is a harsh grating note on an even pitch or slightly modulated, grrreh. When perched, vocabulary more diverse, with most notes having similar tonal quality to flight call, combined with nasal squeals and squawks.

Social and Interspecific Behavior

Degree of Sociality

Tends to roost communally and to feed in groups.

Breeding

Poorly known; birds in breeding condition in September/October. Nests in tree-hollow, e.g., in Gossampinus. Clutch 2–3 eggs. Other data from captivity: incubation ca. 27 days, by both parents; chick has sparse yellow down; nestling remains in the nest for ca. 10 weeks, fed by both adults.

Critically Engandered. CITES I. Formerly common, but all subspecies have been seriously reduced in numbers due to widespread trapping for the avicultural trade, in combination with habitat destruction. Dramatic population decline, particularly in late 20th century; now extinct on many islands and close to extinction on most others. Whereabouts of populations large enough to supply so many birds unknown to scientists; trapping of roosting birds with sticky poles may eliminate whole populations. Subspecies <em>abbotti</em> critically endangered, with only 10 birds encountered in 2008. Probably extirpated on Lombok and close to extinction on Sulawesi, Sumbawa, and Flores; 7 separate sightings of 2–19 birds in Rawa Aopo Watumohai National Park, southeastern Sulawesi in autumn 1995. Not recorded on Nusa Penida (east of Bali) since 1986. Occurrence on a considerable number of islands over an extensive area may mask serious decline throughout most of range. Still fairly common on Komodo, in national park. Global population estimated at fewer than 7000 individuals: 500 on Komodo (despite estimated decline of 60% between 2000 and 2005), 200–300 on Timor Leste, 200–300 on Sulawesi, 20–50 on West Timor, 40–70 on Flores, 50–100 on Sumbawa, 100 on Rinca and c. 700 other birds in total. Precipitous decline almost entirely attributable to national and international trade, but now exacerbated by large-scale logging and habitat destruction. Illegal trapping continues in many areas including Rawa Aopa Watumohai National Park, Buton, and Kadatua islands. Previously considered Endangered, but its rapid ongoing population decline, caused by unsustainable trapping for the cagebird trade, led to uplisting to Critically Endangered in 2000. Each subspecies should now be managed as a separate unit of conservation concern (2). Law enforcement must be improved.

Distribution of the Yellow-crested Cockatoo - Range Map
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Distribution of the Yellow-crested Cockatoo

Recommended Citation

Rowley, I., C. J. Sharpe, P. F. D. Boesman, and G. M. Kirwan (2024). Yellow-crested Cockatoo (Cacatua sulphurea), version 1.2. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.yeccoc1.01.2
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