Cockatoo

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This article is about the family of birds. For the town in Australia, see Cockatoo, Victoria.
Cockatoos

Umbrella Cockatoo
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Family: Cacatuidae
GR Gray, 1840
Subfamily

Microglossinae
Calyptorhynchinae
Cacatuinae

A cockatoo is any of the 21 bird species belonging to the family Cacatuidae. Along with the Psittacidae family (the true parrots), they make up the order Psittaciformes. The name cockatoo originated from the Malay name for these birds, kaka(k)tua (either from kaka "parrot" + tuwah, or "older sister" from kakak "sister" + tua, "old"[verification needed]).

Cockatoos share many features with other parrots including the characteristic curved beak shape and a zygodactyl foot, with two forward toes and two backwards toes. They differ, however in a number of characteristics, including the often spectacular movable headcrest, the presence of a gall bladder and some other anatomical details, and their lack of the Dyck texture feather composition which causes the bright blues and greens seen in true parrots. Cockatoo species are also, on average, larger than the true parrots (however, the cockatiel is a small cockatoo and the very large parrots include the Hyacinth Macaw by length and the Kakapo by weight). Placement of the cockatoos as a separate family is fairly undisputed, but it is not resolved whether or not other living lineages of parrots (such as the lories) are as distinct as they are.

Cockatoos have a much more restricted range than the true parrots, occurring naturally only in Australia and nearby islands. Eleven of the 21 species exist in the wild only in Australia, while seven species occur in Indonesia, New Guinea, and other south Pacific islands. Three species occur in both New Guinea and Australia.

Contents

  • 1 Cockatoos as endangered or vulnerable species
  • 2 Systematics and evolution
  • 3 References
  • 4 External links

[edit] Cockatoos as endangered or vulnerable species

All species of cockatoo are protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (also known as CITES), which makes the import, export and trade in all wild-caught parrots and cockatoos illegal.

The following cockatoo species are protected on the CITES appendix 1 list of endangered species.

All of the other cockatoo species are protected on the CITES appendix 2 list of vulnerable species.

[edit] Systematics and evolution

Phylogeny of the family Cacatuidae based on Brown & Toft (1999)

Brown & Toft (1999) reviewed the existing evidence and additional mitochondrial 12S rRNA sequence data to arrive at a well-supported phylogeny of the cockatoos. They could distinguish 3 subfamilies:

  1. The all-black Palm Cockatoo represents distinct lineage that diverged early; it was previously sometimes grouped with the other black species but this is incorrect.
  2. The dark cockatoos; sexually dichromatic species which have ample melanin in their plumage and some red, yellow or orange on wing, tail and face, barred feathers on wing, tail and/or body as well as contrasting ear area spotting in females, while males have the corresponding feathers unbarred and may lack the ear spotting. This group includes the remaining black cockatoos, the Gang-gang Cockatoo and, interestingly, the cockatiel which had previously been placed in a subfamily of its own (Nymphicinae) or even as a broad-tailed parrot.
  3. The remaining species, which are all hypomelanistic and not sexually dimorphic.

The genera Calyptorhynchus and Cacatua can be further resolved into two subgenera each, and in the latter case as a distinct third lineage the white-and-pink Major Mitchell's Cockatoo, which is intermediate in coloration between the grey-and-pink Galah and the white Cacatua. It is best recognized as a monotypic genus Lophocroa. Indeed, pending further research, all subgenera could conceivably be raised to genus rank.

Intron 7 of nuclear β-fibrinogen sequence data suggests that the Microglossinae may have diverged later, and that the cockatiel might be distinct enough to warrant recognition of the Nymphicinae (Astuti, 2004?), but in other aspects agrees with the rRNA and newly-interpreted morphological data.

The fossil record of cockatoos is even more limited than that of parrots in general, with only one truly ancient cockatoo fossil known: A species of Cacatua, most probably subgenus Licmetis, was found in Early Miocene (16-23 mya) deposits of Riversleigh, Australia (Boles, 1993). In Melanesia, subfossil bones of Cacatua species which apparently did not survive early human settlement were found on New Caledonia and New Ireland[citation needed]. The bearing of these fossils on cockatoo evolution and phylogeny is fairly limited, except that the Riversleigh fossil allows some tentative dating of the divergence of subfamilies.

A sulphur-crested cockatoo
A cockatoo's eye

FAMILY CACATUIDAE