Yellow Tailed Black Cockatoo - Calyptorhynchus Funereus
The yellow tailed black cockatoo is a large cockatoo native to the south-east of Australia measuring 55–65 cm (22–26 in) in length. It has a short crest on the top of its head. Its plumage is mostly brownish black and it has prominent yellow cheek patches and a yellow tail band. The body feathers are edged with yellow giving a scalloped appearance. The adult male has a black beak and pinkish-red eye-rings, and the female has a bone-colored beak and grey eye-rings. In flight, yellow-tailed black cockatoos flap deeply and slowly, with a peculiar heavy fluid motion. Their loud, wailing calls carry for long distances.
The yellow-tailed black cockatoo is 55–65 cm (22–26 in) 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 tails of birds of subspecies funereus measure around 33 cm (13 in), with an average tail length 5 cm (2.0 in) longer than xanthanotus. Male funereus birds weigh on average around 731 g (1.612 lb) and females weigh about 800 g (1.8 lb). Birds of the xanthanotus race on the mainland average heavier than the Tasmanian birds; the males on the mainland weigh on average around 630 g and females 637 g (1.404 lb), while those on Tasmania average 583 and 585 g (1.290 lb) respectively. Both mainland and Tasmanian birds of the xanthanotus race average about 28 cm (11 in) in tail length. The plumage is a more solid brown-black in the eastern subspecies, while the southern race has more pronounced yellow scalloping on the underparts.
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-colored bill, and brighter and more clearly defined yellow cheek-patches. Immature birds have duller plumage overall, a horn-colored 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 (upper beak), suited to digging out grubs from tree branches and trunks. Records of the timing of the eye ring changing from grey to pink in male birds are sparse, but have been recorded anywhere from one to four years of age. Australian farmer and amateur ornithologist John Courtney proposed that the similarity between juvenile and female eye rings prevented adult males becoming aggressive to younger birds. He also observed the eye rings to flush brighter in aggressive males. Molting appears to take place in stages over the course of a year, and is poorly understood.
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.
Within the species, two subspecies are recognized:
C. f. funereus, the nominate form, is known as the eastern yellow-tailed black cockatoo.
C. f. xanthanotus, known as the southern yellow-tailed black cockatoo.
Distribution and Habitat
The yellow-tailed black cockatoo is found up to 2,000 m (6,600 ft) above sea level over southeastern Australia including the island of Tasmania and the islands of the Bass Strait (King, Flinders, Cape Barren islands), and also on Kangaroo Island. On Tasmania and the islands of the Bass Strait it is the only native black-coloured cockatoo. On the mainland, it is found from the vicinity of Gin Gin and Gympie in south and central eastern Queensland, south through New South Wales, where it occurs along the Great Dividing Range and to the coast, and into and across most of Victoria bar the northern and northwestern corner, to the Coorong and Mount Lofty Ranges in southeastern South Australia. A tiny population numbering 30 to 40 birds inhabits the Eyre Peninsula. There they are found in sugar gum (Eucalyptus cladocalyx) woodland in the lower peninsula and migrate to the mallee areas in the northern peninsula after breeding. There is evidence that birds on the New South Wales south coast move from elevated areas to lower lying areas towards the coast in winter. They are generally common or locally very common in a wide range of habits, although they tend to be locally rare at the limits of their range. Their breeding range is restricted to areas with large old trees.
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. They have also spread to parts of suburban Sydney, particularly on or near golf courses, pine plantations and parks, such as Centennial Park in the eastern suburbs. It is unclear whether this is adaptive or because of loss of habitat elsewhere. In urban Melbourne, they have been recorded at Yarra Bend Park. The "Black Saturday bushfires" of 2009 appear to have caused sufficient loss of their natural habitat for them to have been sighted in other parts of the urban areas of Melbourne as well. Unlike other cockatoos, a large proportion of the yellow-tailed black cockatoo's diet is made up of wood-boring grubs; they also eat seeds. They nest in hollows high in trees with fairly large diameters, generally Eucalyptus. Although they remain common throughout much of their range, fragmentation of habitat and loss of large trees suitable for nesting has caused population decline in Victoria and South Australia. In some places yellow-tailed black cockatoos appear to have adapted to humans and they can often be seen in parts of urban Canberra, Sydney, Adelaide and Melbourne. The species is not commonly seen in aviculture, especially outside Australia.
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 his crest and spreading his tail feathers to display his yellow plumage. Softly growling, he approaches the female and bows to her three or four times. His eye ring may also flush a deeper pink. Nesting takes place in large vertical tree hollows of tall trees, generally eucalypts, which may be 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. A 1994 study of nesting sites in Eucalyptus regnans forest in the Strzelecki Ranges in eastern Victoria found the average age of trees used for hollows by the yellow-tailed black cockatoo to be 228 years.
Hollows can be 1 to 2 metres (3.3 to 6.6 ft) deep and 0.25–0.5 metres (9.8–19.7 in) wide, with a base of wood chips. 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 (22 in) high by 30 cm (12 in) wide at the mouth, and at least 65 cm (26 in) deep, in a tree which measured 72 cm (28 in) 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 lusterless 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 (2 × 1.4 in). 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 grayish 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.
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