Yellow-tailed black cockatoo

Appearance

The yellow-tailed black cockatoo is 55–65 cm in length and 750–900 grams in weight.

It has a short mobile crest on the top of its head, and the plumage is mostly brownish-black with paler feather-margins in the neck, nape, and wings, and pale yellow bands in the tail feathers.

The male yellow-tailed black cockatoo has a black bill, a dull yellow patch behind each eye, and pinkish or reddish eye-rings.

The female has grey eye-rings, a horn-coloured bill, and brighter and more clearly defined yellow cheek-patches. Immature birds have duller plumage overall, a horn-coloured bill, and grey eye-rings; The upper beak of the immature male darkens to black by two years of age, commencing at the base of the bill and spreading over ten weeks. The lower beak blackens later by four years of age. The elongated bill has a pointed maxilla, suited to digging out grubs from tree branches and trunks.

The yellow-tailed black cockatoo is distinguished from other dark-plumaged birds by its yellow tail and ear markings, and its contact call. Parts of its range overlap with the ranges of two cockatoo species that have red tail banding, the red-tailed cockatoo and the glossy black cockatoo. Crow species may appear similar when seen flying at a distance; however, crows have shorter tails, a quicker wing beat, and different calls.

Naming

The yellow-tailed black cockatoo was first described in 1794 by the English naturalist George Shaw as ''Psittacus funereus'', its specific name ''funereus'' relating to its dark and sombre plumage, as if dressed for a funeral. The French zoologist Anselme Gaëtan Desmarest reclassified it in the new genus ''Calyptorhynchus'' in 1826. The genus name is derived from the Greek words καλυπτός "hidden" and ῥύγχος "beak".

Distribution

The yellow-tailed black cockatoo is found up to 2,000 m AMSL over southeastern Australia including the island of Tasmania and the islands of the Bass Strait, and also on Kangaroo Island.

Behavior

Yellow-tailed black cockatoos are diurnal, raucous and noisy, and are often heard before being seen.

They make long journeys by flying at a considerable height while calling to each other, and they are often seen flying high overhead in pairs, or trios comprising a pair and their young, or small groups.

Outside of the breeding season in autumn or winter they may coalesce into flocks of a hundred birds or more, while family interactions between pairs or trios are maintained. They are generally wary birds, although they can be less shy in urban and suburban areas. They generally keep to trees, only coming to ground level to inspect fallen pine or banksia cones or to drink. Flight is fluid and has been described as "lazy", with deep, slow wingbeats.

Tall eucalypts that are emergent over other trees in wooded areas are selected for roosting sites. It is here that the cockatoos rest for the night, and also rest to shelter from the heat of the day. They often socialise before dusk, engaging in preening, feeding young, and flying acrobatically. Flocks will return to roost earlier in bad weather.

The usual call is an eerie high-pitched wailing contact call, ''kee-ow ... kee-ow ... kee-ow'', made while flying or roosting, and can be heard from afar. Birds may also make a harsh screeching alarm call. They also make a soft, chuckling call when searching for cossid moth larvae. Adults are normally quiet when feeding, while juveniles make frequent noisy begging calls. The superb lyrebird can mimic the adult yellow-tailed black cockatoo's contact call with some success.

Habitat

The birds may be found in a variety of habitats including grassy woodland, riparian forest, heathland, subalpine areas, pine plantations, and occasionally in urban areas, as long as there is a plentiful food supply.

Reproduction

The breeding season varies according to latitude, taking place from April to July in Queensland, January to May in northern New South Wales, December to February in southern New South Wales, and October to February in Victoria, South Australia and Tasmania.

The male yellow-tailed black cockatoo courts by puffing up crest and spreading his tail feathers to display his yellow plumage. Softly growling, he approaches the female and bows three or four times to her. His eye ring may also flush a deeper pink.

Nesting takes place in large vertical tree hollows of tall trees, generally eucalypts, which are either living or dead. Isolated trees are generally chosen, so birds can fly to and from them relatively unhindered. The same tree may be used for many years.

Hollows can be 1 to 2 metres deep and 0.25–0.5 metres wide, with a base of woodchips. A chance felling of a eucalypt known to have been used as a nesting tree near Scottsdale in northeastern Tasmania allowed accurate measurements to be made, yielding a hollow measuring 56 cm high by 30 cm wide at the mouth, and at least 65 cm deep, in a tree which measured 72 cm in diameter below the hollow.

Both the male and female prepare the hollow for breeding, which involves peeling or scraping off wood shavings from the inside the hollow to prepare bedding for the eggs. Gum leaves are occasionally added as well.

The clutch consists of one or two white lustreless rounded oval eggs which may have the occasional lime nodule. The first egg averages around 47 or 48 mm long and 37 mm in diameter . The second egg is around 2 mm smaller all over and is laid two to seven days later.

The female incubates the eggs alone and begins after the completion of laying. She enters the hollow feet first, and is visited by the male who brings food two to four times a day. Later both parents help to raise the chicks. The second chick is neglected and usually perishes in infancy. Information on the breeding of birds in the wild is lacking; however, the incubation period in captivity is 28–31 days.

Newly hatched chicks are covered with yellow down and have pink beaks that fade to a greyish white by the time of fledging. Chicks fledge from the nest three months after hatching, and remain in the company of their parents until the next breeding season.


Like other cockatoos, this species is long-lived. A pair of yellow-tailed black cockatoos at Rotterdam Zoo stopped breeding when they were 41 and 37 years of age, but still showed signs of close bonding. Birds appear to reach sexual maturity between four and six years of age; this is the age range of breeding recorded in captivity.

Food

The diet of the yellow-tailed black cockatoo is varied and available from a range of habitats within its distribution, which reduces their vulnerability to degradation or change in habitat.

Much of the diet comprises seeds of native trees, particularly she-oaks, but also ''Eucalyptus'', ''Acacia'', ''Banksia' , and ''Hakea'' species.

They are also partial to pine cones in plantations of the introduced ''Pinus radiata'' and to other introduced trees, including ''Cupressus torulosa'', ''Betula pendula'' and the buds of elm ''Ulmus'' species. In the Eyre Peninsula, the yellow-tailed black cockatoo has become dependent on the introduced Aleppo pine , alongside native species.

The yellow-tailed black cockatoo is very fond of the larvae of tree-boring beetles, such as the longhorn beetle ''Tryphocaria acanthocera'', and cossid moth ''Xyleutes boisduvali''. Birds seek them out all year but especially in June and July, when the moth caterpillars are largest, and they are accompanied by their just fledged young.

They search out holes and make some exploratory bites looking for larvae. If successful, they peel and tear down a strip of bark to make a perch for themselves before continuing to gouge and excavate the larvae, which have deeply tunneled into the heartwood.

Yellow-tailed black cockatoos have been reported flocking to ''Banksia'' cones ten days after bushfire as the follicles open. With pine trees, they prefer green cones, nipping them off at the stem and holding in one foot, then systematically lifting each segment and extracting the seed. A cockatoo spends about twenty minutes on each pine cone.

They drink at various places, from stock troughs to puddles, and do so in the early morning or late in the afternoon. Insect larvae and Fabaceae seeds are among food reported to have been fed to young.