Red-tailed black cockatoo

 

From - Wikipedia,

 By - Vinuri Randhula Silva,

The red-tailed black cockatoo (Calyptorhynchus banksii) also known as Banksian- or Banks' black cockatoo, is a large black cockatoo native to Australia. Adult males have a characteristic pair of bright red panels on the tail that gives the species its name. It is more common in the drier parts of the continent. Five subspecies are recognised, differing chiefly in beak size. Although the more northerly subspecies are widespread, the two southern subspecies, the forest red-tailed black cockatoo and the south-eastern red-tailed black cockatoo are under threat.

The red-tailed black cockatoo's closest relative is the glossy black cockatoo; the two species form the subgenus Calyptorhynchus within the genus of the same name. They are distinguished from the other black cockatoos of the subgenus Zanda by their significant sexual dimorphism and calls of the juveniles; one a squeaking begging call, the other a vocalization when swallowing food.

Red-tailed black cockatoos are around 60 centimetres (24 in) in length and sexually dimorphic. The male's plumage is all black with a prominent black crest made up of elongated feathers from the forehead and crown. The bill is dark grey. The tail is also black with two lateral bright red panels. Females are black with yellow-orange stripes in the tail and chest, and yellow grading to red spots on the cheeks and wings. The bill is pale and horn-coloured. The underparts are barred with fine yellow over a black base. Male birds weigh between 670 and 920 grams (1.5–2 lb), while females weigh slightly less at 615–870 grams (1.25–1.75 lb). In common with other cockatoos and parrots, red-tailed black cockatoos have zygodactyl feet, two toes facing forward and two backward, that allow them to grasp objects with one foot while standing on the other, for feeding and manipulation. Black cockatoos are almost exclusively left-footed (along with nearly all other cockatoos and most parrots)

Juvenile red-tailed black cockatoos resemble females until puberty, which occurs around four years of age, but have paler yellow barred underparts. As the birds reach maturity, males gradually replace their yellow tail feathers with red ones; the complete process takes around four years.

As with other cockatoos, the red-tailed black cockatoo can be very long-lived in captivity; in 1938, ornithologist Neville Cayley reported one over fifty years old at Taronga Zoo. Another bird residing at London and Rotterdam Zoos was 45 years and 5 months of age when it died in 1979.

Several calls of red-tailed black cockatoos have been recorded. The bird's contact call is a rolling metallic krur-rr or kree, which may carry long distances and is always given while flying; its alarm call is sharp. Displaying males vocalize a sequence of soft growling followed by a repetitive kred-kred-kred-kred.

The male red-tailed black cockatoo courts by puffing up crest and cheek feathers, and hiding the beak; it then sings and struts, ending in a jump and a flash of red tail feathers toward the female who will most often reply by defensively biting him. Breeding generally takes place from May to September except in the case of the South-eastern subspecies, which nests during summer (December to February). Pairs of the subspecies samueli in the Wheatbelt region of Western Australia may produce two broods, while those of South-eastern subspecies only produce one. Nesting takes place in large vertical tree hollows of tall trees. 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 (3–7 ft) deep and 0.25–0.5 metres (10–20 in) wide, with a base of woodchips. A clutch consists of 1 to 2 white, lustreless eggs, although the second chick is in most cases neglected and perishes in infancy.

Although red-tailed black cockatoos feed on a wide variety of native and introduced grains, the mainstay of their diet is eucalyptus seeds. There is a specific relationship between the species and larger-fruited species of gums. These vary across Australia but include the marri in Southwest Western Australia, 

References

1.  BirdLife International (2012). "Calyptorhynchus banksii". IUCN Red List of Threatened Species. 2012. Retrieved 26 November 2013.