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Cockatoo
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A cockatoo is any of the 21 bird species belonging to the family Cacatuidae. Along with the Psittacidae family (the true parrots) and the Nestoridae family, 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").
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A cockatoo is any of the 21 bird species belonging to the family Cacatuidae. Along with the Psittacidae family (the true parrots) and the Nestoridae family, 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"). 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 and lorikeets) are as distinct as they appear. The family has an Australasian distribution, ranging from the Philippines and the eastern Indonesian islands of Wallacea to New Guinea, the Solomon Islands and Australia.
Cockatoos are, on average, larger than true parrots; however, the Cockatiel, the smallest cockatoo, is a small bird, while some of the largest parrots, including the Hyacinth Macaw (the longest parrot) and the flightless Kakapo (the heaviest parrot), are true parrots. Their plumage is generally less colourful than that of the other parrots, being mainly white, grey or black with some colour elsewhere. Like other parrots they have strong bills and feet.
The diet of the cockatoos is composed of seeds, tubers, corms, fruit, flowers and insects. They often feed in large flocks, particularly if they feed on the ground. Cockatoos are monogamous and nest in tree hollows.
Cockatoos are popular birds in aviculture; although, for some species, the largely illegal trade in wild-caught parrots has threatened their survival. Some cockatoo species are threatened by habitat loss and particularly by the loss of suitable hollows for nesting as large, mature trees are cleared; conversely, some species have adapted well to human changes and are considered agricultural pests.
Distribution and habitat
is restricted to the islands of Tanimbar in Indonesia; however a few feral escapees are found in Singapore.]]
Cockatoos have a much more restricted range than the true parrots, occurring naturally only in Australasia. Eleven of the 21 species exist in the wild only in Australia, while seven species occur in the islands of Indonesia, New Guinea, the Philippines and the Solomon Islands. Interestingly, no cockatoo species are found in Borneo or many Pacific Islands, although fossil remains have been recorded from New Caledonia.
Three species occur in both New Guinea and Australia. Some species have widespread distributions, for example the Galah occurs over most of Australia, whereas other species have tiny distributions, confined to a small part of the continent, such as the Long-billed 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, Hong Kong and Palau, 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. The most widespread species are open country specialists that feed on grass seeds. Species may also occupy woodlands, rainforests, shrublands and even alpine forests. Several species have adapted well to human modified habitats, and are found in agricultural areas and even busy cities.
Morphology and description
has an elongated bill used for digging for food in the ground]]
The cockatoos are generally large to medium sized parrots, with one species, the Cockatiel, being quite smaller than the other species. 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.
Like other parrots, cockatoos have short, strong claws, and walk with a waddle, often using their strong bill as a third limb when climbing through branches. They generally have long broad wings used in rapid flight, with speeds of 70 km/h or more being recorded. The black cockatoos, however, along with Major Mitchell's Cockatoo, have shorter, more rounded wings and a more leisurely flight.
Cockatoos have large bills which are kept sharp by rasping the two mandibles together when resting. The bills are complemented by large muscular tongues which help manipulate seeds inside the bills so that they can be de-husked before eating. During the de-husking the lower mandible applies the pressure, the tongue holds the seed in place and the upper mandible acts as an anvil.
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, and usually on the crest or tail. A few species, like the Galah, have larger areas of colour. In addition to their plumage many species have brightly coloured bare areas around the eye and face, with the Palm Cockatoo having a large red patch of bare skin across the face. A few species exhibit sexual dimorphism in the plumage, with this being most pronounced in the Gang-gang Cockatoo and the Cockatiel. Sexual differences in plumage are more common in the black cockatoos, but many cockatoos vary slightly in overall size and weight, with the males being, on average, larger. The iris colour is often brown in adult females and differs from the black irises often seen in adult males, but this may not be totally reliable to identify the sex of a cockatoo.
Behaviour
Cockatoos are diurnal, requiring daylight to find their food. They are not early risers, instead waiting until the sun has warmed their roosting sites before feeding. The 21 species are generally highly social and will roost, forage and travel together, often in large flocks. All species require roosting sites that are sometimes located near drinking sites, but many species may travel great distances between the roosting sites and feeding sites.
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.
Calls and communication
The vocalisations of cockatoos are loud and harsh. They serve a number of functions, including allowing individuals to recognise one another, warning 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 Short-billed Black Cockatoo has as many as 15 different calls, whereas others, such as Major Mitchell's Cockatoo, have fewer. Some, like the Gang-gang Cockatoo, are comparatively quiet, but do have softer growling calls when feeding. In addition to vocalisations, the Palm Cockatoos communicate over large distances by drumming on a dead branch with a stick. Cockatoo species also make a characteristic hissing sound when threatened.
Diet and feeding
s feed on the ground in flocks that range from 10 to 1000 birds]]
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. Cockatoos may feed either individually or in flocks that range in size from small to quite immense. The Galahs, corellas and some of the black cockatoos feed primarily on the ground, others feed mostly in trees. 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.
While some cockatoos are generalists taking a wide range of foods, others are specialists. The Glossy Black Cockatoo specialises in the cones of Allocasuarina, often a single species, which it holds in its foot and shreds with its powerful bill before removing the seeds with its tongue. Some species take large numbers of insects, particularly when breeding. 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. During times of plenty, they may only need to feed for a few hours in the day, in the morning and evening, and spend the rest of the day loafing, but during the winter most of the day may be spent foraging. During hard times the cockatoos also display versatility in their diet, travelling widely in order to find food, feeding on more green plant material and in some species using their large bills to dig up corms.
Breeding
Cockatoos are monogamous breeders, with pair bonds that can last many years. They may also display site fidelity, returning to the same nesting sites in consecutive years. Courtship is generally simple, particularly for established pairs, with the black cockatoos alone engaging in courtship feeding. Established pairs do engage in allopreening, but all forms of courtship drop off after incubation begins, possibly due to the strength of the pair-bond.
Like most parrots the cockatoos are cavity nesters, nesting in holes in trees. 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. This competition is particularly intense amongst larger species.
The nesting hollows are lined with sticks, wood chips and branches with leaves. The eggs of cockatoos are oval and initially white, although they become discoloured over the course of incubation. They range in size from 55*40 mm in the Palm Cockatoo to 26*18 mm in the Cockatiel. Clutch size varies amongst the family, with the Palm Cockatoo and some other larger cockatoos laying only a single egg, and the smaller species laying anywhere between two to eight eggs. Amongst 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.
Systematics and evolution
Phylogeny of the family Cacatuidae based on Brown and Toft (1999)
A 1999 genetic study by Brown and Toft 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:
- 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.
- 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.
- The remaining species, which are all hypomelanistic and not sexually dimorphic.
The genera Calyptorhynchus and Cacatua can be further subdivided 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. Some argue that it is best recognized as a monotypic genus Lophochroa as has been suggested by Brown & Toft (1999).
A single study using Intron 7 of nuclear ß-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. However, a recent much more extensive study using five different gene sequences confirmed the study of Brown & Toft (1999), as did the studies by Tokita el at (2007) and Adams et al. (1984)
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 million years ago) deposits of Riversleigh, Australia. In Melanesia, subfossil bones of Cacatua species which apparently did not survive early human settlement were found on New Caledonia and New Ireland.
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.
Family Cacatuidae
- Subfamily Microglossinae
- Subfamily Calyptorhynchinae - dark cockatoos
- Genus Callocephalon
- Genus Nymphicus (tentatively placed here)
- Genus Calyptorhynchus
- Subgenus Calyptorhynchus - black-and-red cockatoos
- Red-tailed Black Cockatoo, Calyptorhynchus (Calyptorhynchus) banksii
- Glossy Black Cockatoo, Calyptorhynchus (Calyptorhynchus) lathami
- Subgenus Zanda - black-and-yellow/white cockatoos
- Yellow-tailed Black Cockatoo, Calyptorhynchus (Zanda) funereus
- Short-billed Black Cockatoo, Calyptorhynchus (Zanda) latirostris
- Long-billed Black Cockatoo, Calyptorhynchus (Zanda) baudinii
displaying crest feathers]]
- Subfamily Cacatuinae - white cockatoos
- Genus Eolophus
- Galah, Eolophus roseicapilla
- Genus Lophocroa
- Major Mitchell's Cockatoo (aka Leadbeater's Cockatoo), Lophocroa leadbeateri (Vigors, 1831)
- Major Mitchell's Cockatoo (aka Leadbeater's Cockatoo), Lophocroa leadbeateri leadbeateri (Vigors, 1831)
- Western Major Mitchell's Cockatoo (aka Leadbeater's Cockatoo), Lophocroa leadbeateri mollis (Mathews, 1912)
- Genus Cacatua
- Subgenus Cacatua - true white cockatoos
- Umbrella Cockatoo, Cacatua (Cacatua) alba (Müller, 1776)
- Sulphur-crested Cockatoo, Cacatua (Cacatua) galerita (Latham, 1790)
- Eleonora Cockatoo, Cacatua (Cacatua) galerita eleonora (Finsch, 1863)
- Fitzroy Cockatoo, Cacatua (Cacatua) galerita fitzroyi (Mathews, 1912)
- Greater Sulphur-crested Cockatoo, Cacatua (Cacatua) galerita galerita (Latham, 1790)
- Triton Cockatoo, Cacatua (Cacatua) galerita triton (Temminck, 1849)
- Moluccan Cockatoo (aka Salmon-crested Cockatoo), Cacatua (Cacatua) moluccensis (Gmelin, 1788)
- Blue-eyed Cockatoo, Cacatua (Cacatua) ophthalmica (Sclater, 1864)
- Yellow-crested Cockatoo (aka Lesser Sulphur-crested Cockatoo), Cacatua (Cacatua) sulphurea (Gmelin, 1788)
- Abbott's Cockatoo, Cacatua (Cacatua) sulphurea abbotti (Oberholser, 1917)
- Citron-crested Cockatoo, Cacatua (Cacatua) sulphurea citrinocristata (Fraser, 1844)
- Djampeana Middle Sulphur-crested Cockatoo, Cacatua sulphurea djampeana Hartert, 1897
- Occidental Lesser Sulphur-crested Cockatoo, Cacatua sulphurea occidentalis
- Timor Cockatoo, Cacatua (Cacatua) sulphurea parvula (Bonaparte, 1850)
- Subgenus Licmetis - corellas
- Ducorps' Cockatoo, Cacatua (Licmetis) ducorpsii (Pucheran, 1853)
- Tanimbar Corella (aka Goffin's Cockatoo), Cacatua (Licmetis) goffiniana (Finsch, 1863)
- Red-vented Cockatoo, Cacatua (Licmetis) haematuropygia (Müller, 1776)
- Western Corella, Cacatua (Licmetis) pastinator (Gould, 1841)
- Little Corella, Cacatua (Licmetis) sanguinea (Gould, 1843)
- Long-billed Corella, Cacatua (Licmetis) tenuirostris (Kuhl, 1820)
Relationship with humans
Aviculture
Cockatoos are very popular as pets, not only for their appearance and their ability to mimic human speech but also for their intelligence and engaging personalities. Well-socialised cockatoos are often affectionate not only to their owner but to strangers as well. In spite of their attractiveness as pets there are drawbacks; they are prone to psychological disorders and are potentially destructive, with the larger cockatoos in particular prone to destructive behaviour. Cockatoos may show aggression during the breeding season; cockatoos are capable of very strong and painful bites. They also require attention, although experts warn against "spoiling" young birds with too much attention as it may make the bird dependent on the owner, leading to problems later in life. Another drawback as a pet is the fact that most cockatoo species are very loud birds, though they naturally only vocalize for short periods of time twice a day. They can be expensive pets, with a cost which typically ranges from $500-$2000 for the more commonly available species. In addition to the actual cost, cockatoos require a very large cage for their size. Cockatoos also require an out of cage gym or perch and a steady supply of toys, branches, cardboard boxes, or other chewable items, which prevents future self destructive behaviour such as feather-plucking and the development of stereotypic behaviour patterns. Cockatoos are capable of living up to 30-70 years depending upon species (around 20 years for the smaller Cockatiels) and as such they require a long term commitment from their owners. Their longevity is also considered a positive trait as it reduces instances of the loss of a pet.
Cockatoos are popular for use in trained bird shows, and they can also be trained as pets. Cockatoos are generally less food motivated than other birds; some birds may be more motivated by a reward of petting or praise than of food. Cockatoos can often be trained to accept a parrot harness, enabling their owners to take them outdoors. Cockatoos have been used in animal-assisted therapy, generally in nursing homes.
In general, the smaller cockatoo species such as Galahs and Goffin's Cockatoos are considered to be much easier to keep as pets than large cockatoos such as Moluccans. In Australia, where Galahs are extremely abundant and inexpensive, they are often considered to be good first birds. The smallest species of cockatoo, the Cockatiel is a non-destructive and less demanding alternative making them extremely popular as pets, and among the species most often recommended to new bird owners.
Popular culture
has a very strong bill and a characteristic face with red cheeks]]
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.
The Palm Cockatoo, which has a unique beak and face colouration, is used as a symbol by the World Parrot Trust.
In Australian slang or vernacular speech a person who is deputed to keep a look-out whilst colleagues undertake clandestine or illegal activities, particularly gambling, may be referred to as a "cockatoo". Proprietors of small agricultural undertakings are frequently jocularly or slightly disparagingly referred to as "cocky farmers".
They have been used frequently in advertising; for example, a cockatoo appeared recently in a 'cheeky' advertising campaign for Cockatoo Ridge Wineries. The advertisement featured former Miss Australia Erin McNaught with a Sulphur-crested Cockatoo perched on her shoulder, beside the sexually implicit slogan "She loves a cockatoo". The advertisement received mixed reactions from the public. It was later pulled from circulation in favour of an alternative picture beside the slogan ' Who's a cheeky girl, then? ' - a common expression taught to domesticated cockatoos.
Pests
Cockatoos can be serious agricultural pests. 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; in suburbia, they may chew outdoor furniture, door and window frames, and soft decorative timbers such as Western Red Cedar are readily demolished. Birds may also target external wiring and fixtures such as solar water heaters, television antennae and satellite dishes. A business in central Melbourne suffered as Sulphur-crested Cockatoos repeatedly stripped the silicone sealant from the plate glass windows. Galahs and Red-tailed Black Cockatoos have stripped electrical cabling in rural areas, and tarpaulin is targetted elsewhere. Several cockatoo species, especially Australian ones, are regarded as pests in some places, at some times or in particular circumstances.
- The Short-billed 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. They are also known to damage nut and fruit crops, and have learnt to exploit Canola crops.
- The Long-billed Black Cockatoo, also endemic to the south-west of Western Australia, can be a pest in in apple and pear orchards where it destroys the fruit to extract the seeds.
- 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 able to be destroyed where serious damage is being caused by them to trees, vineyards, orchards, recreational reserves and commercial crops. 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.
- 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 chewing wiring and household fittings. 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.
- Butler's Corella (Cacatua pastinator butleri), a subspecies of the Western Corella, is a declared pest of agriculture in Western Australia, where is causes similar damage to that of the Little Corella.
- 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’.
- Outside Australia, the Tanimbar Corella is a pest on Yamdena Island where it raids maize crops.
Status and conservation
on a balcony rail in central Sydney]]
Human activities have had positive effects on some species of cockatoo and negative effects on others. According to the IUCN and BirdLife International seven species of cockatoo are considered to be vulnerable or worse, and a further species is considered to be near threatened. Of these two, the Philippine Cockatoo and the Yellow-crested Cockatoo, are considered to be critically endangered.
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 already, making them vulnerable to the loss of these habitats. Cockatoos are popular as pets, and the capture and trade has threatened some species. For example between 1983 and 1990, 66,654 Moluccan 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. The capture of many species has subsequently been banned, but the trade continues illegally.
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.
Five cockatoo species - 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 1 list of endangered species. All other cockatoo species bar the Cockatiel are protected on the CITES Appendix 2 list of vulnerable species.
Cited text
External links
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- Species descriptions and articles
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- - site explaining many of the responsibilities of cockatoo ownership
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