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Cockatoo
Cockatoo
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Cockatoo
Cockatoo perching on a branch: Its plumage on the top of its head above its eyes is white and it has a horn-coloured beak. The rest of its head, its neck, and most of its front are pink. Its wings and tail are grey.
Sulphur-crested cockatoo
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Superfamily: Cacatuoidea
Family: Cacatuidae
G. R. Gray 1840
Type genus
Cacatua
Genera
Map showing southeastern Asia, Australia, Melanesia, and New Zealand. Islands in the Philippines and the Sunda Islands are colored red, east to the Solomon Islands, as is Australia with Tasmania. New Caledonia is colored blue.
Current range of cockatoos – red
Finds of recent fossils – blue
Synonyms

A cockatoo is any of the 21 species of parrots belonging to the family Cacatuidae, the only family in the superfamily Cacatuoidea. Along with the Psittacoidea (true parrots) and the Strigopoidea (large New Zealand parrots), they make up the order Psittaciformes. The family has a mainly Australasian distribution, ranging from the Philippines and the eastern Indonesian islands of Wallacea to New Guinea, the Solomon Islands and Australia.

Cockatoos are recognisable by their prominent crests and curved bills. Their plumage is generally less colourful than that of other parrots, being mainly white, grey, or black and often with coloured features in the crest, cheeks, or tail. On average, they are larger than other parrots; however, the cockatiel, the smallest cockatoo species, is medium-sized.[3] The phylogenetic position of the cockatiel remains unresolved, except that it is one of the earliest offshoots of the cockatoo lineage. The remaining species are in two main clades. The five large black-coloured cockatoos of the genus Calyptorhynchus form one branch. The second and larger branch is formed by the genus Cacatua, comprising 12 species of white-plumaged cockatoos and three monotypic genera that branched off earlier, namely the pink and grey galah, the mainly grey gang-gang cockatoo and the large black-plumaged palm cockatoo.

Cockatoos prefer to eat seeds, tubers, corms, fruit, flowers, and insects. They often feed in large flocks, particularly when ground-feeding. Cockatoos are monogamous and nest in tree hollows. Some cockatoo species have been adversely affected by habitat loss, particularly from a shortage of suitable nesting hollows after large, mature trees are cleared; conversely, some species have adapted well to human changes and are considered agricultural pests.

Cockatoos are popular birds in aviculture, but their needs are difficult to meet. The cockatiel is the easiest cockatoo species to maintain and is by far the most frequently kept in captivity. White cockatoos are more commonly found in captivity than black cockatoos. Illegal trade in wild-caught birds contributes to the decline of some cockatoo species in the wild.

Etymology

[edit]

The word cockatoo dates from the 17th century and is derived from Dutch kaketoe, which in turn is from the Indonesian/Malay kakatua. Seventeenth-century variants include cacato, cockatoon and crockadore, and cokato, cocatore and cocatoo were used in the 18th century.[4][5] The derivation has also been used for the family and generic names Cacatuidae and Cacatua, respectively.[6]

In Australian slang or vernacular speech, a person who is assigned to keep watch while others undertake clandestine or illegal activities, particularly gambling, may be referred to as a "cockatoo".[7] Proprietors of small agricultural undertakings are often jocularly or slightly disparagingly referred to as "cocky farmers".[8]

Taxonomy

[edit]
Psittaciformes

Strigopidae – New Zealand parrots

Cacatuidae – cockatoos

Psittacidae – African and New World parrots

Psittaculidae – Old World parrots

Cacatuidae

Calyptorhynchus – black cockatoos (2 species)

Zanda – black cockatoos (3 species)

Nymphicus – cockatiel

Probosciger – palm cockatoo

Callocephalon – gang-gang cockatoo

Eolophus – galah

Lophochroa – pink cockatoo

Cacatua – white cockatoos and corellas (13 species)

Genus level cladogram of the cockatoos based on a 2023 molecular phylogenetic study by Brian Smith and collaborators.[9] The number of species in each genus is from the list maintained by Frank Gill, Pamela Rasmussen and David Donsker on behalf of the International Ornithological Committee (IOC), now the International Ornithologists' Union.[10]

The cockatoos were first defined as a subfamily Cacatuinae within the parrot family Psittacidae by English naturalist George Robert Gray in 1840, with Cacatua the first listed and type genus.[11] This group has alternately been considered as either a full or subfamily by different authorities. American ornithologist James Lee Peters in his 1937 Check-list of Birds of the World and Sibley and Monroe in 1990 maintained it as a subfamily, while parrot expert Joseph Forshaw classified it as a family in 1973.[12] Subsequent molecular studies indicate that the earliest offshoot from the original parrot ancestors were the New Zealand parrots of the family Strigopidae, and following this the cockatoos, now a well-defined group or clade, split off from the remaining parrots, which then radiated across the Southern Hemisphere and diversified into the many species of parrots, parakeets, macaws, lories, lorikeets, lovebirds and other true parrots of the superfamily Psittacoidea.[13][14][15][16][17][18][19][20][21]

The relationships among various cockatoo genera are largely resolved,[13][14][16][22][23][24] although the placement of the cockatiel (Nymphicus hollandicus) at the base of the cockatoos remains uncertain. The cockatiel is alternatively placed basal to all other cockatoo species,[13][23] as the sister taxon to the black cockatoo species of the genus Calyptorhynchus[16][22][24] or as the sister taxon to a clade consisting of the white and pink cockatoo genera as well as the palm cockatoo.[14] The remaining species are within two main clades, one consisting of the black species of the genus Calyptorhynchus while the other contains the remaining species.[13][14][16][23][24] According to most authorities, the second clade includes the black palm cockatoo (Probosciger), the grey and reddish galah (Eolophus), and the gang-gang cockatoo (Callocephalon),[13][14][16][23] although Probosciger is sometimes placed basal to all other species.[22] The remaining species are mainly white or slightly pinkish and all belong to the genus Cacatua.[13][14][15][16][23] The genera Eolophus and Cacatua are hypomelanistic. The genus Cacatua is further subdivided into the subgenera Licmetis, commonly known as corellas, and Cacatua, referred to as white cockatoos.[13][22][23][24][25] Confusingly, the term "white cockatoo" has also been applied to the whole genus.[26][27] The five cockatoo species of the genus Calyptorhynchus are commonly known as black cockatoos,[25] and are divided into two subgenera—Calyptorhynchus and Zanda. The former group are sexually dichromatic, with the females having prominently barred plumage.[28] The two are also distinguished by differences in the food-begging calls of juveniles.[29]

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, found in Early Miocene (16–23 million years ago) deposits of Riversleigh, Australia.[30] Although fragmentary, the remains are similar to the western corella and the galah.[31] In Melanesia, subfossil bones of Cacatua species which apparently did not survive early human settlement have been found on New Caledonia and New Ireland.[32][33] The bearing of these fossils on cockatoo evolution and phylogeny is fairly limited, although the Riversleigh fossil does allow tentative dating of the divergence of subfamilies.

Genera and species

[edit]
Closeup of head of black-plumaged cockatoo with bare red skin on its face. It has a large beak, which is open with its tongue visible.
The palm cockatoo has a strong bill and red cheeks. At 55–60 cm (22–24 in) long and weighing 910–1,200 g (2.01–2.65 lb), it is the largest cockatoo.[34]
A mainly black cockatoo perched on a left hand on a sunny day. The cockatoo has a ring on its right leg. The Sydney Harbour Bridge is in the distance
Carnaby's black cockatoo with a zoo keeper at Taronga Zoo Sydney, Australia
A pink and white coloured cockatoo with a raised crest flying against a background of blue sky
Pink cockatoo flying at Taronga Zoo Sydney.

There are about 44 different birds in the cockatoo family Cacatuidae including recognized subspecies. The current subdivision of this family is as follows:[Note 1]

Subfamily Nymphicinae

Subfamily Calyptorhynchinae: Black cockatoos

Subfamily Cacatuinae

Morphology

[edit]
A mainly-white cockatoo with a black beak perched on a wooden perch. Its yellow crest is raised and very conspicuous.
A captive sulphur-crested cockatoo displaying its crest in the U.S.

The cockatoos are generally medium to large parrots of stocky build, which range from 30–60 cm (12–24 in) in length and 300–1,200 g (0.66–2.65 lb) in weight; however, one species, the cockatiel, is considerably smaller and slimmer than the other species, being 32 cm (13 in) long (including its long pointed tail feathers) and 80–100 g (2.8–3.5 oz) in weight.[7][34][36][37] The movable headcrest, which is present in all cockatoos, is spectacular in many species;[38] it is raised when the bird lands from flying or when it is aroused.[39] Cockatoos share many features with other parrots, including the characteristic curved beak shape and a zygodactyl foot, with the two middle toes forward and the two outer toes backward.[40] 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.[37]

Like other parrots, cockatoos have short legs, strong claws, a waddling gait[37] 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 70 km/h (43 mph) being recorded for galahs.[41] 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.[41]

Two grey cockatoos on a lichen-covered tree branch. The red crested male is on the left.
A pair of gang-gang cockatoos in NSW, Australia (male with red head feathers). Cockatoos make lasting pair bonds.

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.[7] 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.[37] 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.[42]

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.[43] The galah and Major Mitchell's cockatoo are more broadly coloured in pink tones.[44] 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 corellas and blue-eyed cockatoo.[44] 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 and glossy black cockatoos.[42] The 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.[42]

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
A white cockatoo's left foot clasping aviary bars showing claws, scaly skin and zygodactyly—the middle two toes forward and the outer two toes backward.

Cockatoos maintain their plumage with frequent 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 gland on their lower back and apply it by wiping their plumage with their heads or already oiled feathers. Powder-down is produced by specialised feathers in the lumbar region and distributed by the preening cockatoo all over the plumage.[45]

Moulting is very slow and complex. Black cockatoos appear to replace their flight feathers 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.[45]

Voice

[edit]

The vocalisations of cockatoos are loud and harsh.[7] 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.[46] Cockatoo species also make a characteristic hissing sound when threatened.[39]

Distribution and habitat

[edit]
A mainly white cockatoo with a few pale-pink feathers on its face. The cockatoo is perched on a branch in a tree standing on its right foot while holding what appears to be a rambutan fruit up to its open beak with its left foot
The Tanimbar corella is restricted to the islands of Tanimbar in Indonesia; a few feral escapees are found in Singapore.

Cockatoos have a much more restricted range than the true parrots, occurring naturally only in Australia, Indonesia, the Philippines, and some Pacific regions.[7] Eleven of the 21 species exist in the wild only in Australia, while seven species occur only in the islands of the Philippines, Indonesia, Papua New Guinea and the Solomon Islands. No cockatoo species are found in Borneo, despite their presence on nearby Palawan and Sulawesi or many Pacific islands,[47] although fossil remains have been recorded from New Caledonia.[32]

Three species occur in both New Guinea and Australia.[48] Some species have widespread distributions, with the galah, for example, occurring over most of Australia, whereas other species have tiny distributions, confined to a small part of the continent, such as the Baudin's black cockatoo of Western Australia or to a small island group, such as the Tanimbar corella, which is restricted to the Tanimbar Islands of Indonesia. Some cockatoos have been introduced accidentally to areas outside their natural range such as New Zealand, Singapore, and Palau,[49] while two Australian corella species have been introduced to parts of the continent where they are not native.

Cockatoos occupy a wide range of habitats from forests in subalpine regions to mangroves. However, no species is found in all types of habitat.[50] The most widespread species,[7] such as the galah and cockatiel,[51] are open-country specialists that feed on grass seeds.[7] They are often highly mobile fast flyers and are nomadic. Flocks of birds move across large areas of the inland, locating and feeding on seed and other food sources. Drought may force flocks from more arid areas to move further into farming areas.[51] Other cockatoo species, such as the glossy black cockatoo, inhabit woodlands, rainforests, shrublands and even alpine forests. The red-vented cockatoo inhabits mangroves and its absence from northern Luzon may be related to the lack of mangrove forests there.[52] Forest-dwelling cockatoos are generally sedentary, as the food supply is more stable and predictable.[53] Several species have adapted well to human modified habitats and are found in agricultural areas and even busy cities.[54]

Behaviour

[edit]
Watercolour and gouache sketch by Henry Stacy Marks

Cockatoos are diurnal and require daylight to find their food.[7] They are not early risers, instead waiting until the sun has warmed their roosting sites before feeding. All species are generally highly social and roost, forage and travel in colourful and noisy flocks. These vary in size depending on availability of food; in times of plenty, flocks are small and number a hundred birds or less, while in droughts or other times of adversity, they may swell up to contain thousands or even tens of thousands of birds; one record from the Kimberley noted a flock of 32,000 little corellas. Species that inhabit open country form larger flocks than those of forested areas.[55]

Some species require roosting sites that are located near drinking sites; other species travel great distances between the roosting and feeding sites.[56] Cockatoos have several characteristic methods of bathing; they may hang upside down or fly about in the rain or flutter in wet leaves in the canopy.[39] Cockatoos have a preferred "footedness" analogous to human handedness. Most species are left-footed with 87–100% of individuals using their left feet to eat, but a few species favor their right foot.[57]

Researchers at Charles Sturt University in Australia have documented spontaneous, individually distinctive, dance-like movements in several cockatoo species. These sequences, which sometimes resemble courtship displays and can occur even without musical stimuli, may indicate complex social and cognitive abilities.[58]

Breeding

[edit]
Two pink-skinned chicks sparsely covered with incompletely formed whitish feathers standing in a plastic bowl. The pre-feathers are round and pointed and are pinkish towards the base fading to white at the tips
Hand-reared white cockatoo chicks bred for sale as pets.

Cockatoos are monogamous breeders, with pair bonds that can last many years. Many birds pair up in flocks before they reach sexual maturity and delay breeding for a year at least. Females breed for the first time anywhere from three to seven years of age and males are often older. Sexual maturity is delayed so birds can develop the skills for raising and parenting young, which is prolonged compared with other birds; the young of some species remain with their parents for up to a year.[59] Cockatoos may also display site fidelity, returning to the same nesting sites in consecutive years.[46] Courtship is generally simple, particularly for established pairs, with the black cockatoos alone engaging in courtship feeding. Established pairs do engage in preening each other, but all forms of courtship drop off after incubation begins, possibly due to the strength of the pair-bond.[60]

Like most parrots, the cockatoos are cavity nesters, nesting in holes in trees,[61] which they are unable to excavate themselves.[62] These hollows are formed from decay or destruction of wood by branches breaking off, fungi or insects such as termites or even woodpeckers where their ranges overlap.[63] In many places these holes are scarce and the source of competition, both with other members of the same species and with other species and types of animal.[64] In general, cockatoos choose hollows only a little larger than themselves, hence different-sized species nest in holes of corresponding (and different) sizes. If given the opportunity, cockatoos prefer nesting over 7 or 8 metres (23 or 26 ft) above the ground[63] and close to water and food.[65]

The nesting hollows are lined with sticks, wood chips and branches with leaves. The eggs of cockatoos are oval and initially white, as their location makes camouflage unnecessary.[66] However, they do become discoloured over the course of incubation. They range in size from 55 mm × 37 mm (2.2 in × 1.5 in) in the palm and red-tailed black cockatoos, to 26 mm × 19 mm (1.02 in × 0.75 in) in the cockatiel.[66] Clutch size varies within the family, with the palm cockatoo and some other larger cockatoos laying only a single egg and the smaller species laying anywhere between two and eight eggs. Food supply also plays a role in clutch size.[67] Some species can lay a second clutch if the first fails.[68] Around 20% of eggs laid are infertile.[69] The cockatoos' incubation and brooding responsibilities may either be undertaken by the female alone in the case of the black cockatoos or shared amongst the sexes as happens in the other species. In the case of the black cockatoos, the female is provisioned by the male several times a day. The young of all species are born covered in yellowish down, bar the palm cockatoo, whose young are born naked.[70] Cockatoo incubation times are dependent on species size, with the smaller cockatiels having a period of around 20 days and the larger Carnaby's black cockatoo incubating its eggs for up to 29 days.[7]

The nestling period also varies by species size, with larger species having longer nestling periods. It is also affected by season and environmental factors and by competition with siblings in species with clutch sizes greater than one. Much of what is known about the nestling period of some species is dependent on aviary studies – aviary cockatiels can fledge after 5 weeks and the large palm cockatoos after 11 weeks.[7] During this period, the young become covered in juvenile plumage while remaining in the hollow. Wings and tail feathers are slow to grow initially but more rapid as the primary feathers appear. Nestlings quickly reach about 80–90% of adult weight about two-thirds of the time through this period, plateauing before they leave the hollow; they fledge at this weight with wing and tail feathers still to grow a little before reaching adult dimensions.[71] Growth rate of the young, as well as numbers fledged, are adversely impacted by reduced food supply and poor weather conditions.[72]

Diet and feeding

[edit]
Two mainly white-plumaged cockatoos on what appears to be a lawn. One cockatoo is standing upright and has a long upper mandible and orange-pink feathers its face and chest. The other cockatoo has its head in the grass with its bill not visible.
Wild long-billed corellas in Perth. The bird on the right is using its long beak to dig for food in short grass.

Cockatoos are versatile feeders and consume a range of mainly vegetable food items. Seeds form a large part of the diet of all species; these are opened with their large and powerful bills. The galahs, corellas and some of the black cockatoos feed primarily on the ground; others feed mostly in trees.[7] The ground-feeding species tend to forage in flocks, which form tight, squabbling groups where seeds are concentrated and dispersed lines where food is more sparsely distributed;[73] they also prefer open areas where visibility is good. The western and long-billed corellas have elongated bills to excavate tubers and roots and the pink cockatoo walks in a circle around the doublegee (Emex australis) to twist out and remove the underground parts.[74]

Many species forage for food in the canopy of trees, taking advantage of serotiny (the storage of a large supply of seed in cones or gumnuts by plant genera such as Eucalyptus, Banksia and Hakea), a natural feature of the Australian landscape in dryer regions. These woody fruiting bodies are inaccessible to many species and harvested in the main by parrots, cockatoos and rodents in more tropical regions. The larger cones can be opened by the large bills of cockatoos but are too strong for smaller animals.[75] Many nuts and fruits lie on the end of small branches which are unable to support the weight of the foraging cockatoo, which instead bends the branch towards itself and holds it with its foot.[76]

While some cockatoos are generalists taking a wide range of foods, others are specialists. The glossy black cockatoo specialises in the cones of trees of the genus Allocasuarina, preferring a single species, A. verticillata. It holds the cones in its foot and shreds them with its powerful bill before removing the seeds with its tongue.[77] Some species take large numbers of insects, particularly when breeding; in fact the bulk of the yellow-tailed black cockatoo's diet is made up of insects. The large bill is used in order to extract grubs and larvae from rotting wood. The amount of time cockatoos have to spend foraging varies with the season.[76] During times of plenty they may need to feed for only a few hours in the day, in the morning and evening, then spend the rest of the day roosting or preening in trees, but during the winter most of the day may be spent foraging. The birds have increased nutritional requirements during the breeding season, so they spend more time foraging for food during this time. Cockatoos have large crops, which allow them to store and digest food for some time after retiring to a tree.[78]

Predators and threats

[edit]

The peregrine falcon and little eagle have been reported taking galahs and the wedge-tailed eagle has been observed killing a sulphur-crested cockatoo.[79] Eggs and nestlings are vulnerable to many hazards. Various species of monitor lizard (Varanus) are able to climb trees and enter hollows. Other predators recorded include the spotted wood owl on Rasa Island in the Philippines; the amethystine python, black butcherbird and rodents including the giant white-tailed rat[80] in Cape York; and brushtail possum on Kangaroo Island. Furthermore, galahs and little corellas competing for nesting space with the glossy black cockatoo on Kangaroo Island have been recorded killing nestlings of the latter species there. Severe storms may also flood hollows drowning the young and termite or borer activity may lead to the internal collapse of nests.[81]

Like other parrots, cockatoos can be afflicted by psittacine beak and feather disease (PBFD). The viral infection causes feather loss and beak malformation and reduces the bird's overall immunity. Particularly prevalent in sulphur-crested cockatoos, little corellas and galahs, it has been recorded in 14 species of cockatoo to date. Although unlikely to significantly impact on large, healthy populations of birds in the wild, PBFD may pose a high risk to smaller stressed populations.[82]

A white cockatoo and a sulphur-crested cockatoo were found to be infected with the protozoon Haemoproteus and another sulphur-crested cockatoo had the malaria parasite Plasmodium on analysis of faecal samples at Almuñecar ornithological garden in Granada in Spain.[83] Like amazon parrots and macaws, cockatoos frequently develop cloacal papillomas. The relationship with malignancy is unknown, as is the cause, although a parrot papilloma virus has been isolated from a grey parrot with the condition.[84]

Social learning

[edit]

Cockatoos have been shown to learn new skills through social interaction. In New South Wales, researchers and citizen scientists were able to track the spread of lid-flipping skills as cockatoos learned from each other to open garbage bins. Bin-opening spread more quickly to neighbouring suburbs than suburbs further away. In addition, birds in different areas developed their own variants for accomplishing the complex task.[85][86]

Relationship with humans

[edit]
A cockatoo is perched on a city balcony several floors above the ground. A suburban landscape is in the background.
A sulphur-crested cockatoo visiting a balcony in eastern Sydney for bird seeds

Human activities have had positive effects on some species of cockatoo and negative effects on others. Many species of open country have benefited greatly from anthropogenic changes to the landscape, with the great increase in reliable seed food sources, and available water contributing to their survival, as well as their adaption to a diet including foreign foodstuffs. This benefit appears to be restricted to Australian species, as cockatoos favouring open country outside Australia have not become more abundant. Predominantly forest-dwelling species have suffered greatly from habitat destruction; in the main, they appear to have a more specialised diet and have not been able to incorporate exotic food into their diet. A notable exception is the yellow-tailed black cockatoo in eastern Australia.[87]

Pests

[edit]

Several species of cockatoo can be serious agricultural pests.[88] They are sometimes controlled by shooting, poisoning or capture followed by gassing. Non-lethal damage mitigation methods used include scaring, habitat manipulation and the provision of decoy food dumps or sacrifice crops to distract them from the main crop. They can be a nuisance in urban areas due to destruction of property. They maintain their bills in the wild by chewing on wood, but in suburbia, they may chew outdoor furniture, door and window frames;[54] soft decorative timbers such as western redcedar are readily demolished.[89] Birds may also target external wiring and fixtures such as solar water heaters,[54] television antennae and satellite dishes.[89] A business in central Melbourne suffered as sulphur-crested cockatoos repeatedly stripped the silicone sealant from the plate glass windows.[90] Galahs and red-tailed black cockatoos have stripped electrical cabling in rural areas and tarpaulin is targeted elsewhere.[90] Outside Australia, the Tanimbar corella is a pest on Yamdena Island where it raids maize crops.[91]

a number of white cockatoos are biting parts of the building wall, leaving chunks of polystyrene missing.
Sulphur-crested cockatoos damaging the Sturt Mall shopping centre facade, made of polystyrene

In 1995 the Government of the state of Victoria published a report on problems caused by long-billed corellas, sulphur-crested cockatoos and galahs, three species which, along with the little corella, have large and growing populations, having benefited from anthropogenic changes to the landscape. Subsequent to the findings and publication of the report, these three species were declared unprotected by a Governor in Council Order under certain conditions and are allowed to be killed where serious damage is being caused by them to trees, vineyards, orchards, recreational reserves and commercial crops.[92] Damage covered by the report included not only that to cereal crops, fruit and nut orchards and some kinds of vegetable crops but also to houses and communications equipment.[93] The little corella is a declared pest of agriculture in Western Australia, where it is an aviculturally introduced species. The birds damage sorghum, maize, sunflower, chickpeas and other crops. They also defoliate amenity trees in parks and gardens, dig for edible roots and corms on sports grounds and race tracks, as well as chew wiring and household fittings.[94] In South Australia, where flocks can number several thousand birds and the species is listed as unprotected, they are accused of defoliating red gums and other native or ornamental trees used for roosting, damaging tarpaulins on grain bunkers, wiring and flashing on buildings, taking grain from newly seeded paddocks and creating a noise nuisance.[95]

Several rare species and subspecies, too, have been recorded as causing problems. The Carnaby's black cockatoo, a threatened Western Australian endemic, has been considered a pest in pine plantations where the birds chew off the leading shoots of growing pine trees, resulting in bent trunks and reduced timber value.[96] They are also known to damage nut and fruit crops,[97] and have learnt to exploit canola crops.[98] The Baudin's black cockatoo, also endemic to the south-west of Western Australia, can be a pest in apple and pear orchards where it destroys the fruit to extract the seeds.[96] Muir's corella, the nominate subspecies of the western corella, is also a declared pest of agriculture in Western Australia, as well as being nationally vulnerable and listed under state legislation as being "rare or likely to become extinct".[99]

Status and conservation

[edit]
Two mainly white-plumaged cockatoos facing each other in a cage. Some feathers at the base of the underside of their tails are red
The red-vented cockatoo is a critically endangered species endemic to the Philippines.[100]
The upper body of a mainly white cockatoo that has raised its left leg to its black beak. Pale-yellow crest feathers are just seen under the more prominent white crest feathers. It has a wide circular rim of featherless blue skin around its eyes. Its irises are brown.
The blue-eyed cockatoo is a vulnerable species endemic to New Britain.[101]

According to the IUCN and BirdLife International, seven species of cockatoo are considered to be vulnerable or worse and one is considered to be near-threatened.[102][103] Of these, two species—the red-vented cockatoo and the yellow-crested cockatoo—are considered to be critically endangered.[104]

The principal threats to cockatoos are habitat loss and the wildlife trade. All cockatoos are dependent on trees for nesting and are vulnerable to their loss; in addition many species have specialised habitat requirements or live on small islands and have naturally small ranges, making them vulnerable to the loss of these habitats.[105] Cockatoos are popular as pets and the capture and trade has threatened some species; between 1983 and 1990, 66,654 recorded salmon-crested cockatoos were exported from Indonesia, a figure that does not include the number of birds caught for the domestic trade or that were exported illegally.[106] The capture of many species has subsequently been banned but the trade continues illegally. Birds are put in crates or bamboo tubing and conveyed on boats out of Indonesia and the Philippines.[107] Not only are the rare species smuggled out of Indonesia but also common and rare cockatoos alike are smuggled out of Australia; birds are sedated, covered in nylon stockings and packed into PVC tubing which is then placed in unaccompanied luggage on international flights.[107] Mortality is significant (30%) and eggs, more easily hidden on the bodies of smugglers on flights, are increasingly smuggled instead. Trafficking is thought to be run by organised gangs, who also trade Australian species for overseas species such as macaws coming the other way.[108]

All species of cockatoo except the cockatiel are protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which restricts import and export of wild-caught parrots to special licensed purposes. Five cockatoo species (including all subspecies)—the Tanimbar corella (Cacatua goffiniana), red-vented cockatoo (Cacatua haematuropygia), Moluccan cockatoo (Cacatua moluccensis), yellow-crested cockatoo (Cacatua sulphurea) and palm cockatoo (Probosciger aterrimus)—are protected on the CITES Appendix I list. With the exception of the cockatiel, all remaining cockatoo species are protected on the CITES Appendix II list.[109]

Aviculture

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Closeup of a wing-clipped white and salmon-coloured cockatoo ruffling its wings and crest and apparently squawking. It has a ring on its left leg.
A wing-clipped pet. Salmon-crested cockatoos, also known as Moluccan cockatoos,[110] are the largest white-coloured cockatoo species at about 52 cm (20 in) long and weighing 775–935 grams.[111] Cockatoos can be noisy and demanding pets.

Kept for their appearance, intelligence, and engaging personalities,[7] cockatoos can nonetheless be problematic pets or companion parrots.[112] Generally, they are not good at mimicking human speech,[113] although the little corella is a renowned talker.[114] As social animals, wild cockatoos have been known to learn human speech from ex-captive birds that have integrated into a flock.[115] Their care is best provided by those experienced in keeping parrots.[112] Cockatoos are social animals and their social needs are difficult to cater for,[112] and they can suffer if kept in a cage on their own for long periods of time.[116]

The cockatiel is by far the cockatoo species most frequently kept in captivity. Among U.S. bird keepers that participated in a survey by APPMA in 2003/04, 39% had cockatiels, as opposed to only 3% that had (other) cockatoo species.[117] The white cockatoos are more often encountered in aviculture than the black cockatoos.[118] Black cockatoos are rarely seen in European zoos due to export restrictions on Australian wildlife but birds seized by governments have been loaned.[119]

Cockatoos are often very affectionate with their owner and at times other people but can demand a great deal of attention. It has been suggested that cockatoos' need for physical attention from humans may stem from suboptimal rearing techniques – young birds being removed from parental care for hand-rearing too early in the belief that this will produce a more suitable pet, leading the bird to seek out physical contact from humans as a parent substitute.[120] Furthermore, their intense curiosity means they must be given a steady supply of objects to tinker with, chew, dismantle and destroy. Parrots in captivity may suffer from boredom, which can lead to stereotypic behaviour patterns, such as feather-plucking. Feather plucking is likely to stem from psychological rather than physical causes.[121] Other major drawbacks include their painful bites,[122] and their piercing screeches.[123] The salmon-crested[124] and white cockatoo species are particular offenders.[125] All cockatoos have a fine powder on their feathers, which may induce allergies in certain people.[122] In general, the smaller cockatoo species such as Goffin's and quieter Galah's cockatoos are much easier to keep as pets.[126] The cockatiel is one of the most popular and easiest parrots to keep as a pet,[127][128] and many colour mutations are available in aviculture.[36]

A slender mainly grey male crested parrot with a yellow and orange head perched on a horizontal wooden branch placed high in a room.
A pet cockatiel. This parrot is about 32 cm (13 in) long and is by far the smallest and lightest cockatoo.

Larger cockatoos can live 30 to 70 years depending on the species, or occasionally longer, and cockatiels can live for about 20 years. As pets they require a long-term commitment from their owners. Their longevity is considered a positive trait as it reduces instances of the loss of a pet.[7] The oldest cockatoo in captivity was a pink cockatoo named Cookie, residing at Brookfield Zoo in Chicago, which lived to be 83 years old (1933–2016).[129][130][131] A salmon-crested cockatoo named King Tut who resided at the San Diego Zoo was nearly 69 when he died in 1990 and a palm cockatoo reached 56 in London Zoo in 2000.[132] However, anecdotal reports describe birds of much greater ages.[132] Cocky Bennett of Tom Ugly's Point in Sydney was a celebrated sulphur-crested cockatoo who was reported to have reached an age of 100 years or more. He had lost his feathers and was naked for much of his life.[133] A palm cockatoo was reported to have reached 80 or 90 years of age in an Australian zoo,[46] and a little corella that was removed from a nest in central Australia in 1904 was reported still alive in the late 1970s.[79] In February 2010, a white cockatoo named Arthur was claimed to be 90 years old; he had lived with a family for generations in Dalaguete, Cebu, before being taken to Cebu City Zoo.[134]

Trained cockatoos are sometimes seen in bird shows in zoos. They are generally less motivated by food than other birds; some may respond more to petting or praise than food. Cockatoos can often be taught to wear a parrot harness, enabling their owners to take them outdoors. Cockatoos have been used in animal-assisted therapy, generally in nursing homes.[135]

Cockatoos often have pronounced responses to musical sounds and numerous videos exist showing the birds dancing to popular music. Research conducted in 2008 with an Eleonora cockatoo named Snowball had indicated that this particular individual is indeed capable of beat induction—perceiving human-created music and synchronizing his body movements to the beat.[136]

Culture

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Dutch still life with cockatoo, circa 1640

The earliest European depiction of a cockatoo is in the falconry book De arte venandi cum avibus, written by Frederick II, Holy Roman Emperor.[137] The next European depiction of a cockatoo, previously thought to be the earliest, is present in the 1496 painting by Andrea Mantegna titled Madonna della Vittoria. Later examples were painted by Hungarian artist Jakob Bogdani (1660–1724), who resided in Amsterdam from 1683 and then England,[138] and appeared with numerous other birds in the bird pieces of the Dutch painter Melchior d'Hondecoeter (1636–1695).[139] A cockatoo is the unlucky subject in An Experiment on a Bird in the Air Pump by English artist Joseph Wright of Derby, its fate unclear in the painting.[140] Cockatoos were among the many Australian plants and animals which featured in decorative motifs in Federation architecture of the early 20th century.[141] A visit to a Camden Town pet shop in 1958 inspired English painter William Roberts to paint The Cockatoos, in the collection of the Tate Gallery.[142][143] American artist and sculptor Joseph Cornell was known for placing cutout paper cockatoos in his works.[144]

The government of the Australian Capital Territory adopted the gang-gang cockatoo as its official faunal emblem on 27 February 1997.[145] The short-lived budget airline Impulse Airlines featured a sulphur-crested cockatoo on its corporate livery (and aeroplanes).[146] The palm cockatoo, which has a unique beak and face colouration, is used as a symbol by the World Parrot Trust.[147]

Two 1970s police dramas featured protagonists with pet cockatoos. In the 1973 film Serpico, Al Pacino's character had a pet white cockatoo and the television show Baretta saw Robert Blake's character with Fred the Triton cockatoo.[148] The popularity of the latter show saw a corresponding rise in popularity of cockatoos as pets in the late 1970s.[149] Cockatoos have been used frequently in advertising; a cockatoo appeared in a 'cheeky' (and later toned-down) 2008 advertising campaign for Cockatoo Ridge Wineries.[150]

Intelligence

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A team of scientists from Oxford University, the University of Vienna and the Max Planck Institute conducted tests on ten untrained Tanimbar corellas (Cacatua goffiniana), and found that they were able to solve complex mechanical puzzles.[151]

Notes

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
Cockatoos are parrots comprising the family Cacatuidae, which includes 21 species divided among eight genera and is the sole family within the superfamily Cacatuoidea. The English name "cockatoo" derives from Dutch "kaketo(e)", borrowed from Malay "kakatua", possibly onomatopoeic of the bird's cry or from "kakak tua" meaning "elder sibling". These birds are endemic to Australasia, ranging from the Philippines and Indonesian islands through New Guinea and the Solomon Islands to Australia and nearby Pacific archipelagos. They are distinguished by prominent erectile crests used for signaling, robust curved beaks adapted for cracking nuts and seeds, zygodactyl feet for grasping, and plumage typically in white, black, or grey tones accented with yellow, pink, or red. Native to diverse wooded habitats from rainforests to savannas, cockatoos are highly social, often forming large flocks outside breeding season and maintaining lifelong monogamous pair bonds with biparental care in tree cavities. Their intelligence is evident in behaviors such as tool use for foraging, puzzle-solving, and vocal mimicry, making them popular but demanding pets that require extensive interaction to prevent behavioral issues like feather-plucking. Many species face threats from habitat destruction, illegal pet trade, and invasive species, leading to endangered or vulnerable statuses for over half, with international protections under CITES regulating commerce.

Taxonomy

Phylogenetic Position and Evolution

Cockatoos constitute the monophyletic family Cacatuidae, the sole family within the superfamily Cacatuoidea, which forms one of three primary superfamilies in the order Psittaciformes alongside Psittacoidea (true parrots) and Strigopoidea (New Zealand parrots). This classification is supported by multilocus molecular phylogenies and whole-genome analyses that delineate Cacatuidae as a basal lineage distinct from the more derived Psittacoidea, based on shared derived traits such as movable head crests and unique cranial kinesis, corroborated by genetic markers rather than solely morphological convergence. Genomic evidence underscores their separation, with cockatoos exhibiting distinct mitochondrial and nuclear gene arrangements that reflect an ancient split, prioritizing sequence divergence over superficial bill or foot similarities shared ancestrally across parrots. Molecular clock estimates, calibrated against fossil constraints, place the divergence of Cacatuidae from Psittacidae (representing Psittacoidea) at approximately 40.7 million years ago during the Eocene (95% confidence interval: 51.6–30.3 Ma), marking an early radiation within Psittaciformes likely driven by Gondwanan vicariance and subsequent dispersal. This timeline aligns with Eocene climatic shifts that favored arboreal adaptations, where zygodactyl feet—two toes forward and two backward—evolved as a mechanical solution for precise branch grasping and manipulative feeding, enabling exploitation of hard-shelled seeds in forested niches without reliance on ground foraging. Similarly, the reinforced bill structure, with a hinged upper mandible, represents a causal adaptation for shear-force cracking of nuts and seeds, selected in environments where such resources demanded high mechanical leverage over softer fruits targeted by other parrot lineages. These traits, while plesiomorphic to Psittaciformes, diversified in cockatoos through iterative selection pressures in isolation from continental parrot radiations. The fossil record, though sparse due to the fragility of parrot bones, provides empirical anchors in the Australia-New Guinea region, with early Miocene (23–16 Ma) specimens like the Riversleigh cockatoo from Queensland deposits indicating a size comparable to modern Cacatua species and confirming Australasian origins post-Eocene divergence. Crown-group Cacatuidae diversification accelerated around 27.9 Ma in the Oligocene (95% CI: 38.1–18.3 Ma), coinciding with Miocene aridification and sclerophyllous vegetation expansion in Australia, which likely intensified selective pressures for specialized feeding and crested signaling amid habitat fragmentation. Limited pre-Miocene fossils underscore reliance on genetic proxies over fragmentary osteology, as avian taphonomy biases against small-bodied arboreal taxa, yet available evidence refutes recent African or South American origins in favor of vicariant Gondwanan ancestry.

Genera and Species

The family Cacatuidae consists of 21 species divided among six genera: Cacatua, Calyptorhynchus, Probosciger, Callocephalon, Nymphicus, and Eolophus. All species are endemic to Australasia, encompassing Australia, New Guinea, the Indonesian islands of Wallacea, and parts of Melanesia, with no native occurrences outside this region. The genus Cacatua is the most speciose, containing 11 species primarily characterized by white plumage, including the sulphur-crested cockatoo (C. galerita), which ranges widely across northern and eastern Australia, New Guinea, and eastern Indonesia. The genus Calyptorhynchus includes three species of black cockatoos restricted to Australia, such as the red-tailed black cockatoo (C. banksii). Probosciger comprises a single species, the palm cockatoo (P. aterrimus), distributed in New Guinea and Cape York Peninsula in Australia. The remaining genera each hold one species: the galah (Eolophus roseicapillus) in Eolophus, the cockatiel (Nymphicus hollandicus) in Nymphicus, and the gang-gang cockatoo (Callocephalon fimbriatum) in Callocephalon. Speciation in Cacatuidae has been shaped by geographic isolation, with vicariance events—such as the separation of southwestern Australian populations from eastern ones due to aridification—promoting divergence, alongside allopatric processes in island chains versus the continental mainland. This pattern accounts for higher species diversity in peripheral islands like those of Wallacea compared to the relatively uniform mainland fauna.

Recent Taxonomic Developments

A 2020 phylogeographic study using mitochondrial and nuclear DNA from over 200 red-tailed black-cockatoo (Calyptorhynchus banksii) samples identified a distinct western Australian lineage, formally described as the subspecies C. b. escondidus, diverging approximately 1.7 million years ago and challenging prior morphological lumping of populations based on plumage and calls alone. This revision highlighted genetic isolation driven by arid barriers, prioritizing molecular data for subspecies delimitation over traditional traits like tail panel color variation. In December 2024, a museomics analysis sequenced whole genomes from 16 museum specimens of the yellow-crested cockatoo (Cacatua sulphurea), validating up to seven historical subspecies—four previously recognized (abbotti, parvus, sulphurea, paulandrewi)—and revealing deep phylogenetic structure among Wallacean island populations, with divergence times spanning 0.5–2 million years. The study emphasized genomic evidence of cryptic diversity over morphological similarity in white plumage and crest patterns, supporting refined taxonomy for conservation amid rapid declines. Building on this, a January 2025 genomic synthesis of Wallacean white cockatoos reclassified the Cacatua sulphurea complex into three cryptic species—lesser sulphur-crested (C. sulphurea), citron-crested (C. citrinocristata), and an intermediate lineage—based on fixed genetic markers and low interbreeding signals, overriding earlier synonymy reliant on subtle crest yellowing differences. These data-driven splits underscore how whole-genome approaches expose hidden divergences in morphologically conservative taxa, informing targeted protections against hybridization risks in reintroductions.

Physical Characteristics

Morphology and Plumage

Cockatoos exhibit a body length ranging from 30 to 60 centimeters, classifying them as medium to large parrots with substantial mass relative to other avian groups. Their bills are robust and strongly hooked, providing mechanical leverage to crack tough seeds and nuts, a adaptation evident in comparative studies of parrot beak morphology. The feet are zygodactyl, featuring two toes directed forward and two backward, which facilitates secure perching and manipulation of food items in arboreal environments. Plumage in cockatoos is typically dominated by white, black, or grey tones, with less vibrant coloration compared to other parrot families, serving camouflage functions in open woodlands. Sexual dimorphism is generally minimal across species, often limited to subtle iris color differences, though exceptions occur in certain black cockatoos where females display barred patterns or reddish undertail coverts absent in males. Cockatoos possess powder down feathers, specialized structures that disintegrate into a fine keratin powder during preening, which coats the plumage to enhance waterproofing and remove contaminants, an adaptation supporting hygiene in variable environmental conditions.

Crest and Display Features

Cockatoos feature an erectile crest consisting of elongated feathers originating from a muscular ridge atop the skull, enabling voluntary erection through contractions of underlying muscles attached to the feather bases. This mechanism allows precise control, with the crest deployable in seconds to amplify visual signals during interactions. Unlike static ornaments, the crest functions dynamically in conspecific communication, conveying emotional states, intentions, and environmental alerts such as predator proximity via observable raising patterns. In threat displays, individuals raise the crest to increase apparent body size, deterring rivals or predators; empirical field observations document this in aggressive encounters where the expanded silhouette combines with postural changes to assert dominance. For courtship, the crest elevates during greeting rituals or pair bonding, signaling receptivity or affiliation, as seen in captive studies where raised crests accompany approach behaviors without aggressive posturing. These displays rely on the crest's visibility, with rapid flicking or sustained erection differentiating subtle mood variations, supported by consistent anecdotal records from long-term observations of multiple species. Crest morphology varies across species, influencing display efficacy; in the sulphur-crested cockatoo (Cacatua galerita), recurved yellow feathers form a forward-curving structure that fans prominently when raised, enhancing threat or affiliation signals in open woodland settings. Conversely, the palm cockatoo (Probosciger aterrimus) possesses a long, slender crest erected stiffly during territorial and mating sequences, integrating with tool-based drumming—where males rhythmically strike hollows with modified sticks—to broadcast possession and attract females, as verified through audio-visual analyses of wild populations in northern Australia. Such variations underscore the crest's adaptation for species-specific signaling mechanics, prioritizing visual emphasis in dense forest habitats.

Vocalizations

Cockatoos produce a broad array of vocalizations, including harsh screeches, squawks, whistles, and softer contact calls, which acoustic analyses characterize by their harmonic richness and frequency modulation. These sounds typically feature prominent fundamental frequencies with overlaid harmonics, enabling clear transmission over distances. In the sulphur-crested cockatoo (Cacatua galerita), calls can attain intensities of 120 to 135 dB, an adaptation for signaling across expansive, open habitats where visual contact is intermittent. Contact calls predominate in flock contexts, serving to coordinate group movements during foraging and flight; empirical observations show call rates increasing with group size, countering expectations of dilution effects and instead promoting cohesion through repeated auditory cues. Learned elements in these vocalizations, such as dialect variations across populations, further support individual recognition and social bonding, as documented in studies of wild parrots including cockatoos. This complexity arises from syrinx anatomy allowing dual-voice production, facilitating simultaneous emission of varied notes for efficient communication in dynamic environments. Vocal mimicry occurs in several species, with individuals replicating conspecific calls, environmental noises, or anthropogenic sounds; captive experiments confirm this capacity, as in palm cockatoos (Probosciger aterrimus) imitating drum-like beats via modified vocal output. In wild settings, such mimicry likely reinforces foraging coordination by simulating alarm or food signals, though direct causal links require further acoustic mapping; it does not imply abstract intent but stems from iterative learning tied to survival needs like group synchronization.

Habitat and Distribution

Geographic Range

Cockatoos (family Cacatuidae) are endemic to the Australasian biogeographic region, with native distributions spanning Australia (including Tasmania), New Guinea, eastern Indonesia (including Wallacea), the Philippines, and adjacent Pacific islands such as those in Melanesia up to the Solomon Islands. There are no naturally occurring populations in the Americas, Africa, or other continental regions outside this core area, reflecting their evolutionary origins and historical biogeography confined to the Indo-Pacific. Several species exhibit range expansions correlated with anthropogenic landscape changes, particularly agricultural development. The galah (Eolophus roseicapilla), originally distributed across central and northern Australia, has extended southward into South Australia and western regions, including areas previously unoccupied, facilitated by the provision of open grasslands and water sources from farming practices since the mid-20th century. This contrasts with assumptions of widespread contraction, as modified habitats have enabled population growth and colonization of settled districts. Human-mediated introductions have led to established non-native populations demonstrating invasive potential. Sulphur-crested cockatoos (Cacatua galerita), primarily from escaped cage birds supplemented by possible vagrants, formed feral groups in New Zealand starting in the late 19th century, with current distributions scattered across the North Island and estimated totals below 1,000 individuals as of recent surveys. These populations continue to expand locally, underscoring the species' adaptability beyond native ranges.

Habitat Preferences

Cockatoos primarily inhabit environments providing both arboreal nesting sites and proximate open ground for resource access, including eucalypt woodlands, savannas, and rainforest fringes across their Australasian range. These preferences stem from the need for large tree hollows in mature specimens for breeding, coupled with adjacent clearings that facilitate detection of ground-level food. Empirical observations confirm selection for such heterogeneous mosaics over uniform forest interiors, as evidenced by foraging habitat choices in species like the glossy black-cockatoo, which favors sheoak-dominated woodlands with interspersed grassy understories. Many cockatoo taxa demonstrate pronounced habitat generalism, readily exploiting anthropogenically altered landscapes such as urban peripheries and agricultural zones where supplemental seeds, fruits, and water enhance survival rates beyond those in unmodified wilds. Sulphur-crested cockatoos, for example, have proliferated in cities like Sydney by leveraging waste grains and garden produce, with roost sites shifting seasonally toward built-up areas offering thermal refuge and reduced predation. This adaptability underscores causal drivers like opportunistic resource patronage over fidelity to "pristine" conditions, enabling range expansions into novel matrices. Little corellas exemplify arid-zone resilience, persisting in central Australia's deserts through aggregation at artificial or semi-permanent water points amid sparse acacia scrub and spinifex grasslands. Nesting remains tied to infrequent riverine eucalypts providing hollows, yet population stability hinges less on extensive canopy cover than on mitigating competition from co-occurring parrots and invasives for these cavities. Studies of Carnaby's cockatoo reveal that hollow occupancy rates correlate more strongly with exclusion of rivals via entrance modifications than with raw hollow abundance, implicating interference dynamics as primary bottlenecks amid habitat fragmentation. Such patterns affirm that while tree loss curtails options, competitive exclusion—exacerbated by habitat compression—drives localized declines more directly than absolute acreage deficits.

Ecology and Behavior

Diet and Foraging Strategies

Cockatoos (family Cacatuidae) maintain an opportunistic omnivorous diet dominated by plant matter, including seeds (comprising up to 54% in species like the sulphur-crested cockatoo), fruits, nuts, bulbs, corms, roots, and inflorescences, with insects and larvae providing supplementary protein. Their powerful, chisel-like bills facilitate processing hard-shelled foods by cracking seeds and excavating tubers, adapting to diverse textures and defenses in native eucalypt-dominated habitats. This varied intake reflects first-principles energy maximization, as cockatoos select resources yielding high caloric returns relative to handling costs. Foraging strategies emphasize efficiency in heterogeneous environments, with diurnal activity concentrated in early mornings and late afternoons to exploit peak resource availability while minimizing predation exposure. Ground-based gleaning and digging predominate (around 68% of observations in urban-adjacent sulphur-crested populations), targeting grass seeds and underground storage organs, while arboreal feeding (22%) focuses on canopy fruits and seeds; flocks systematically scan and strip patches, depleting high-value items like pine cones that offer 16,864 J/g energy—27% higher than many native alternatives—enabling rapid intake to meet daily needs of approximately 726 kJ. Seasonal shifts occur without major dietary overhaul but with increased ground excavation in drier periods, underscoring adaptability to scarcity through exploitation of emergent, high-density patches over less efficient dispersed foraging. This opportunism extends to non-native resources when natural yields falter, as empirical energy budgets demonstrate raids on calorie-dense alternatives stem from survival imperatives rather than intent, with species like Carnaby's cockatoo consuming over 85% of available pine seeds in plantations to offset protein deficits in native diets via volume. Such behaviors highlight causal drivers of resource selection—nutrient density and accessibility—prioritizing net energy gain, which can incidentally overlap with human-modified landscapes but originates in ecological realism unbound by anthropocentric valuations.

Social Structure and Group Dynamics

Cockatoos form fission-fusion societies characterized by fluid, nomadic flocks that assemble and disband based on foraging opportunities and safety needs, typically ranging from 10 to over 100 individuals, though roosting sites can host up to 500 birds for enhanced vigilance against predators. Foraging subgroups are often smaller, with 41% consisting of 1-5 members and 20% of 6-10, reflecting pragmatic alliances that prioritize resource access over permanent bonds; pair affiliations remain loose outside breeding contexts, allowing individuals to shift groups dynamically. This structure, observed in field studies of species like the sulphur-crested cockatoo, reduces individual risk through collective detection and dilution effects during nomadic movements across habitats. Dominance hierarchies within these flocks are linear and stable, enforced via aggressive displays such as bill threats and postures, which empirically limit costly fights by establishing clear ranks for resource priority. In sulphur-crested cockatoos, males consistently outrank females, and adults dominate juveniles, with hierarchies persisting across fission-fusion cycles at communal roosts, as documented in long-term observations spanning multiple years. These ranks facilitate orderly access to food and perches, minimizing intra-group conflict and supporting efficient group cohesion without relying on kin-based favoritism, though contextual kin associations occur. Urban populations exhibit amplified group dynamics, with larger aggregations forming around reliable human-derived food sources like waste bins, where flocks synchronize with anthropogenic activity peaks to maximize intake. This adaptation, evident in expanding sulphur-crested cockatoo numbers in cities, leverages hierarchy for innovative foraging—higher-ranked birds lead in accessing secured resources—demonstrating opportunistic scaling of flock size to exploit novel, clumped provisions while maintaining core fission-fusion flexibility.

Breeding and Reproduction

Cockatoos generally form long-term monogamous pairs that exhibit breeding site fidelity, with pairs returning to the same tree hollows across seasons. Nesting occurs in large tree hollows, where females typically lay clutches of 1-3 eggs, most commonly two, spaced several days apart. Incubation, primarily by the female but with male assistance in some species, lasts 25-30 days, resulting in synchronous or near-synchronous hatching. Breeding is often seasonal and cued by environmental factors such as food abundance, with peak laying periods varying by species and region—for instance, September in palm cockatoos. Access to reliable food resources, including anthropogenic sources like canola fields, has been linked to improved reproductive outcomes in species such as Carnaby's cockatoo. Fledging success rates are empirically low, often around 66-75% per nest, with high nestling mortality; in two-egg clutches, typically only one chick survives to fledge due to sibling competition and other factors. Both parents contribute to brooding and provisioning, with males often foraging for food to regurgitate for the female and chicks. Nestlings fledge after 8-12 weeks but remain dependent on parental care for 3-6 months until achieving full independence, varying by species—shorter in smaller white cockatoos and longer in larger black cockatoos. This extended post-fledging period reflects the K-selected life history strategy common in the family, prioritizing few offspring with high parental investment over rapid reproduction.

Predators and Natural Threats

Adult cockatoos face predation primarily from large raptors, including the wedge-tailed eagle (Aquila audax), which sporadically preys on species such as Carnaby's black cockatoo (Calyptorhynchus latirostris), and the peregrine falcon (Falco peregrinus), capable of taking adults in flight. Other birds of prey, such as little eagles (Hieraaetus morphnoides), also target cockatoos, particularly fledglings and weakened individuals. Nest predators pose significant risks to eggs and chicks, with goannas (monitor lizards of the genus Varanus, such as the lace monitor V. varius) climbing trees to raid hollows containing cockatoo nests, consuming eggs and nestlings. Pythons, including carpet pythons (Morelia spilota), exploit arboreal nesting sites by constricting and devouring chicks or eggs, a predation strategy observed across Australian parrot species reliant on tree cavities. Diseases represent a chronic natural threat, with psittacine beak and feather disease (PBFD), caused by beak and feather disease virus (BFDV) in the family Circoviridae, inducing feather loss, beak deformities, and immunosuppression in wild cockatoos, leading to secondary infections and high mortality in affected populations. Starvation occurs during seasonal droughts or food shortages, though cockatoo populations demonstrate resilience in habitats with abundant eucalypt resources, where foraging success mitigates baseline mortality, with annual adult survival rates around 70-90% reported in some studies. Competition for limited large tree hollows constrains breeding success, as evidenced by aggressive interactions among sulphur-crested cockatoos (Cacatua galerita) and other species vying for suitable cavities, where dominant pairs can monopolize sites, potentially limiting nesting opportunities in dense populations. This resource limitation, inherent to the slow formation of mature hollows in native forests, acts as a density-dependent factor influencing breeding success.

Cognitive Abilities

Intelligence and Problem-Solving

Goffin's cockatoos (Cacatua goffiniana) demonstrate notable problem-solving abilities in controlled experiments, such as sequentially unlocking a puzzle box secured by five interlocking mechanisms to access a nut reward, with untrained individuals succeeding after brief exposure. These birds also innovate composite tool use, manipulating multiple objects simultaneously—like combining a rigid tool to pierce a barrier and a flexible one to retrieve food—indicating flexible causal understanding rather than rote imitation. However, such feats are primarily observed in captive settings with enriched environments, and wild applications appear opportunistic, tied to foraging in unpredictable island habitats rather than systematic planning. Tool use among cockatoos is uncommon and species-specific; palm cockatoos (Probosciger aterrimus) manufacture and modify drumsticks from branches or seed pods to produce rhythmic beats on hollow trees, a behavior linked to territorial displays and mate attraction, with individuals showing preferences for tool design that affects sound quality. In contrast, Goffin's cockatoos exhibit tool-making in lab puzzles, such as selecting and transporting appropriate implements ahead of time, but this does not extend broadly across the family, where most species rely on beak and foot dexterity without manufactured aids. These capacities reflect adaptive intelligence for exploiting variable resources, measurable through success rates in multi-step tasks (e.g., 7 of 10 Goffin's solved lock sequences), rather than implying advanced sentience akin to mammalian cognition. Evidence for mirror self-recognition is absent in tested cockatoo species; Goffin's cockatoos failed mark tests, showing no directed responses to facial marks visible only in reflections, unlike some corvids that pass with contingency checks. This limitation underscores that cockatoo intelligence prioritizes practical problem-solving over self-conceptual awareness, aligning with evolutionary pressures for environmental manipulation in flock-based, food-scarce niches.

Social Learning and Behavioral Innovations

Sulphur-crested cockatoos (Cacatua galerita) in urban Sydney suburbs have developed a multi-step technique to lift household bin lids using beak and feet, granting access to discarded food; this behavior emerged independently in multiple locations and spread through social observation rather than individual trial-and-error, as demonstrated by controlled experiments where naive birds learned faster after watching trained demonstrators than when learning alone. Geographic clustering of bin-opening hotspots, with regional variants in lid-lifting sequences (e.g., lifting from the side versus front), further indicates local traditions maintained via flock interactions, persisting even as human countermeasures like bin straps evolve in response. Observations from 2018–2020 across 735 suburbs quantified the behavior's diffusion, with prevalence rising from isolated innovators to over 10% of flocks in affected areas within years. In 2025, a novel drinking innovation appeared in the same species, where urban cockatoos manipulate public water fountains by pecking buttons or levers to release streams, enabling hydration during dry periods; initial adopters in Sydney's inner suburbs transmitted this via roost proximity, though spread remains patchy compared to bin-opening, limited to flocks within 5–10 km radii without cross-roost diffusion yet observed. This adaptation exploits anthropogenic water sources amid climate variability, with video analyses confirming emulation over asocial learning in juvenile observers. Foraging innovations in agricultural contexts, such as coordinated crop-raiding in flocks of species like the galah (Cacatua roseicapilla), show localized spread of tactics like timing raids to evade deterrents or targeting vulnerable field edges; while direct causation studies are sparse, flock fission-fusion dynamics facilitate transmission, mirroring urban patterns where successful exploiters attract followers. These behaviors prioritize caloric gains—e.g., bin contents providing 20–50% supplemental energy in winter—over non-utilitarian displays, with no evidence of arbitrary or aesthetically driven innovations persisting without survival payoffs. Experimental limits in captive Goffin's cockatoos (Cacatua goffiniana) confirm social transmission of tool-based foraging but underscore reliance on observable cues for practical outcomes, not symbolic or decontextualized creativity.

Human Interactions

Agricultural Pests and Economic Impacts

Sulphur-crested cockatoos (Cacatua galerita) and corella species (Cacatua sanguinea, Cacatua tenuirostris) are major pests in Australian agriculture, inflicting damage on sunflowers, cereals like wheat and sorghum, fruits including grapes and stone fruits, and nuts such as almonds and pistachios. Flocks target ripening seeds and fruits, with recorded yield losses up to 95% in some unprotected grape blocks (average 14%) and 5-42% in nut crops like walnuts and hazelnuts. In peanuts, red-tailed black cockatoos (Calyptorhynchus banksii) cause an average 7.3% yield reduction (ranging 0-31.8%), contributing to district-level losses of $28,167 in direct damage plus $7,500 indirect in one 1998 case. Overall, cockatoo-inclusive bird damage to horticulture totals approximately $300 million annually (2007 AUD), with perceived losses highest in nuts (22%) and stone fruits (16%). Beyond crops, cockatoos chew electrical infrastructure and buildings to abrade their beaks, exacerbating economic costs. Sulphur-crested cockatoos damaged Australia's National Broadband Network (NBN) fiber optic cables, incurring repair costs of $80,000 by 2017 through repeated gnawing of spare lines. Similar behaviors lead to failures in power lines, street lighting (243 repairs in the Australian Capital Territory due to suspected bird damage), and structural harm to homes and commercial facades, amplifying maintenance expenses in rural and urban-fringe areas. These impacts compete with livestock feed resources by depleting germinating cereals, though quantified competition data remains limited compared to direct crop raids. Management strategies emphasize exclusion and deterrence over broad protection, with netting proving most effective for high-value crops, achieving up to 100% damage reduction at damage thresholds exceeding 15-25% and costing around $1,900 per hectare. Scaring via gas guns, visual predators, and shooting yields short-term reductions (e.g., 48% in vineyards) but faces habituation; integrating with population reduction enhances outcomes. Targeted culling through shooting, trapping, or poisoning (e.g., alphachloralose achieving 50% flock reduction) demonstrates practical success in Victorian programs, lowering complaints and damage without standalone long-term population control due to high reproduction rates, prioritizing cost-benefit in high-impact zones over uniform conservation.

Aviculture and Captive Management

Cockatoos are maintained in captivity for exhibition in zoos and as companion animals, with species such as the umbrella cockatoo (Cacatua alba) and Moluccan cockatoo (C. moluccensis) favored for their vocal mimicry abilities and affectionate behaviors toward handlers. These parrots demand expansive enclosures to accommodate their flight needs and prevent behavioral issues; minimum dimensions for single birds often exceed 3 meters in length, width, and height, with aviaries preferred for pairs or groups to allow natural movement and reduce stress from confinement. Inadequate space contributes to aggression, stereotyped pacing, and feather-plucking, underscoring the necessity for environmental enrichment including perches, swings, and destructible toys mimicking foraging; captive diets should approximate wild variety with seeds, nuts, fruits, vegetables, and formulated pellets, where plain unsweetened rolled oats can be safely incorporated in moderation (10-20% of the diet) dry or cooked without additives to supply fiber and nutrients while mitigating obesity risks from excess carbohydrates. Captive lifespans range from 40 to 70 years or more for larger species, necessitating lifelong commitment from owners, yet high relinquishment rates—often due to unanticipated noise levels exceeding 120 decibels, destructive chewing of household items, and intense bonding requirements—overload rescues and sanctuaries. Empirical observations indicate that many cockatoos cycle through multiple owners, with some individuals accumulating 7 to 11 homes over decades, exacerbating welfare strains and occasionally resulting in escapes that seed feral populations ill-equipped for wild survival. Breeding programs in captivity support conservation for threatened taxa by producing surplus individuals for release, as demonstrated by reproductive success in species like the Philippine cockatoo (C. haematuropygia), where clutch sizes average 2-3 eggs with fledging rates improved via artificial incubation and hand-rearing. However, welfare challenges persist, including pair incompatibility leading to chronic stress and the risks of inbreeding in small founder populations without genetic monitoring. Quarantine protocols, minimizing interspecies contact to avert diseases like psittacosis, are standard in institutional settings to safeguard breeding stock.

Conservation Status and Policy Debates

The conservation status of cockatoo species varies widely, with several classified as critically endangered by the IUCN due to poaching, habitat destruction, and trade. The yellow-crested cockatoo (Cacatua sulphurea) exemplifies acute vulnerability, with an estimated 1,200-2,000 mature individuals remaining globally as of recent assessments, primarily in Indonesia and introduced populations elsewhere. Similarly, the Philippine cockatoo (Cacatua haematuropygia) numbers 430-750 individuals, confined to fragmented Philippine habitats. In contrast, species like the galah (Eolophus roseicapilla) are listed as least concern, with populations increasing across Australia due to adaptation to modified landscapes. Conservation initiatives include targeted interventions, such as the installation of artificial nest boxes in Hong Kong's urban parks in 2025 to address nesting site loss for the feral yellow-crested cockatoo population of approximately 200 birds, which represents about 10% of the global wild total. These efforts aim to mimic natural tree hollows amid urban expansion, though their long-term efficacy remains unproven given ongoing pressures like competition for resources. Empirical data on urban adaptability, particularly for species like the sulphur-crested cockatoo (Cacatua galerita), indicate reduced extinction risks; these birds exploit artificial food sources, roosting sites, and water in cities, sustaining large flocks despite habitat fragmentation. Policy debates center on balancing protections with practical management, especially in Australia where native species protections under the Environment Protection and Biodiversity Conservation Act impose severe penalties—such as $250,000 fines for unauthorized habitat clearing or harming protected cockatoos like black species (Calyptorhynchus spp.). Critics, including horticulturalists, argue these regulations are overly punitive for controlling abundant pest populations (e.g., corellas or galahs damaging crops), favoring collaboration over fines that deter farmers without addressing root causes like overabundance from landscape changes. Habitat offset schemes, requiring developers to fund equivalent restoration elsewhere, face skepticism for their measurable benefits, as relocated sites often fail to support viable populations due to poor monitoring and ecological mismatches. Such policies, while aimed at preventing localized declines, may inadvertently prioritize regulatory compliance over evidence-based pest mitigation, given the resilience of adaptable cockatoos in human-dominated environments.

Cultural Representations

In Indigenous Australian cultures, specific cockatoo species serve as totems linked to songlines and Dreaming narratives. The glossy black cockatoo holds cultural importance among Aboriginal groups, appearing in stories that convey ancestral knowledge and environmental connections. Black cockatoos, including Carnaby's cockatoo known as "Ngoolark" to the Noongar people, symbolize strength and resilience, with their flocks historically darkening skies and integrating into daily observations of nature. These roles reflect practical totemic associations rather than universal spiritual archetypes, grounded in regional ecological observations. Cockatoos feature in historical European art, evidencing early awareness of Australasian fauna through trade or exchange. Illustrations of likely sulphur-crested or yellow-crested cockatoos appear in a 13th-century Vatican manuscript, predating known direct European contact with Australia. Similarly, Andrea Mantegna's 1496 painting Madonna della Vittoria depicts a sulphur-crested cockatoo, prompting analysis of medieval maritime routes from northern Australia to Europe. Such representations often symbolize exoticism or rarity, without deeper symbolic consistency across contexts. In contemporary media, cockatoos illustrate behavioral intelligence, as seen with Snowball, a sulphur-crested cockatoo whose videos of spontaneous synchronization to music rhythms gained widespread attention starting in 2008. Scientific analysis of Snowball's 14 distinct moves, including voguing and head-bobbing, confirms voluntary entrainment to beats, a trait linked to vocal learning species and paralleling human musicality without implying cultural equivalence. This ethological foundation has amplified public fascination with cockatoo cognition, distinct from folklore portrayals of species like black cockatoos as rain predictors based on pre-storm behaviors in Australian settler accounts.

References

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