Editing Cockatoo (section)

==Morphology==
[[File:Cacatua galerita -perching on branch -crest-8a-2c.jpg|right|thumb|A captive [[sulphur-crested cockatoo]] displaying its crest in the U.S.|alt=A mainly-white cockatoo with a black beak perched on a wooden perch. Its yellow crest is raised and very conspicuous.]]
The cockatoos are generally medium to large parrots of stocky build, which range from {{convert|30|–|60|cm|abbr=on}} in length and {{convert|300|–|1200|g|lb|abbr=on}} in weight; however, one species, the cockatiel, is considerably smaller and slimmer than the other species, being {{convert|32|cm|abbr=on}} long (including its long pointed tail feathers) and {{convert|80|–|100|g|abbr=on}} in weight.<ref name = "HBW"/><ref name="Forshaw (2006). plate 1."/><ref name="Forshaw (2006). plate 6.">{{harvnb|Forshaw|2006|p=plate 6}}</ref><ref name=Cam1>{{Harvnb|Cameron|2007|p=1}}.</ref> The movable [[Crest (feathers)|headcrest]], which is present in all cockatoos, is spectacular in many species;<ref>{{Harvnb|Cameron|2007|p=57}}.</ref> it is raised when the bird lands from flying or when it is aroused.<ref name=Forshaw110/> Cockatoos share many features with other parrots, including the characteristic curved beak shape and a [[Dactyly#In birds|zygodactyl]] foot, with the two middle toes forward and the two outer toes backward.<ref>{{Harvnb|Cameron|2007|p=69}}.</ref> They differ in the presence of an erectile crest and their lack of the [[Dyck texture]] feather composition which causes the bright blues and greens seen in true parrots.<ref name=Cam1/>

Like other parrots, cockatoos have short legs, strong claws, a waddling gait<ref name=Cam1/> and often use their strong bill as a third limb when climbing through branches. They generally have long broad wings used in rapid flight, with speeds up to {{convert|70|km/h|abbr=on}} being recorded for galahs.<ref name=Cam67>{{Harvnb|Cameron|2007|p=67}}.</ref> The members of the genus ''Calyptorhynchus'' and larger white cockatoos, such as the [[sulphur-crested cockatoo]] and the [[pink cockatoo]], have shorter, rounder wings and a more leisurely flight.<ref name=Cam67/>
[[File:Callocephalon fimbriatum (pair) -NSW -Australia-8.jpg|thumb|left|A pair of [[gang-gang cockatoo]]s in NSW, Australia (male with red head feathers). Cockatoos make lasting [[pair bond]]s.|alt=Two grey cockatoos on a lichen-covered tree branch. The red crested male is on the left.]]
Cockatoos have a large bill, which is kept sharp by rasping the two jaws together when resting. The bill is complemented by a large muscular tongue which helps manipulate seeds inside the bill so that they can be de-husked before eating.<ref name = "HBW"/> During the de-husking, the lower jaw applies the pressure, the tongue holds the seed in place and the upper jaw acts as an anvil. The eye region of the skull is reinforced to support muscles which move the jaws sideways.<ref name=Cam1/> The bills of male cockatoos are generally slightly larger than those of their female counterparts, but this size difference is quite marked in the palm cockatoo.<ref name=Cam61>{{Harvnb|Cameron|2007|p=61}}.</ref>

The [[plumage]] of the cockatoos is less brightly coloured than that of the other parrots, with species generally being either black, grey or white. Many species have smaller areas of colour on their plumage, often yellow, pink and red, usually on the crest or tail.<ref>{{Harvnb|Cameron|2007|p=58}}.</ref> The galah and Major Mitchell's cockatoo are more broadly coloured in pink tones.<ref name=Cam59>{{Harvnb|Cameron|2007|p=59}}.</ref> Several species have a brightly coloured bare area around the eye and face known as a periophthalmic ring; the large red patch of bare skin of the palm cockatoo is the most extensive and covers some of the face, while it is more restricted in some other species of white cockatoo, notably the [[corella (bird)|corellas]] and [[blue-eyed cockatoo]].<ref name=Cam59/> The plumage of males and females is similar in most species. The plumage of the female cockatiel is duller than the male, but the most marked [[sexual dimorphism]] occurs in the gang-gang cockatoo and the two species of black cockatoos in the subgenus ''Calyptorhynchus'', namely the [[red-tailed black cockatoo|red-tailed]] and [[glossy black cockatoo]]s.<ref name=Cam61/> The [[iris (anatomy)|iris]] colour differs in a few species, being pink or red in the female galah and the pink cockatoo and red-brown in some other female white cockatoo species. The males all have dark brown irises.<ref name=Cam61/>
[[File:Fuß eines Weißhaubenkakadus.JPG|upright|right|thumb|A [[white cockatoo]]'s left foot clasping aviary bars showing claws, scaly skin and [[Dactyly#In birds|zygodactyly]]—the middle two toes forward and the outer two toes backward.|alt=Closeup of a cockatoo's left foot grasping the wires of a cage. The foot is covered with grey-scaly skin and has four toes each with a dark grey curved claw]]
Cockatoos maintain their plumage with frequent [[preening (bird)|preening]] throughout the day. They remove dirt and oil and realign feather barbs by nibbling their feathers. They also preen other birds' feathers that are otherwise hard to get at. Cockatoos produce preen-oil from a [[uropygial gland|gland]] on their lower back and apply it by wiping their plumage with their heads or already oiled feathers. [[Down feather|Powder-down]] is produced by specialised feathers in the lumbar region and distributed by the preening cockatoo all over the plumage.<ref name=Cam68>{{Harvnb|Cameron|2007|p=68}}.</ref><!-- ref cites whole paragraph as is. Duplicate if extra info inserted -->

[[Moulting]] is very slow and complex. Black cockatoos appear to replace their [[flight feather]]s one at a time, their moult taking two years to complete. This process is much shorter in other species, such as the galah and [[long-billed corella]], which each take around six months to replace all their flight feathers.<ref name=Cam68/>

===Voice===
The [[bird vocalization|vocalisations]] of cockatoos are loud and harsh.<ref name = "HBW"/> They serve a number of functions, including allowing individuals to recognize one another, alerting others of predators, indicating individual moods, maintaining the cohesion of a flock and as warnings when defending nests. The use of calls and number of specific calls varies by species; the Carnaby's black cockatoo has as many as 15 types of call, whereas others, such as the pink cockatoo, have fewer. Some, like the gang-gang cockatoo, are comparatively quiet but do have softer growling calls when feeding. In addition to vocalisations, palm cockatoos communicate over large distances by drumming on a dead branch with a stick.<ref name="Palm"/> Cockatoo species also make a characteristic hissing sound when threatened.<ref name=Forshaw110/>