Carnaby's black cockatoo

Carnaby's black cockatoo and Baudin's black cockatoo were once known collectively as the white-tailed black cockatoo (Calyptorhynchus baudinii) until formally classified as separate species. In a 1933 report on the birds of Lake Grace, Western Australian naturalist Ivan Carnaby wrote of a distinctive population of white-tailed black cockatoos that he named mallee black cockatoos. These birds lived in mallee and sandplains, using their large bills to crack open woody seed pods; the typical form had a long narrow bill it used to extract eucalypt seeds from marri seed pods. He classified the large-billed form as a subspecies of the white-tailed black cockatoo in 1948, giving it the name Calyptorhynchus baudinii latirostris. The epithet latirostris is from the Latin "wide" and "bill". The holotype specimen is from Hopetoun, Western Australia. Among the black cockatoos, the two Western Australian white-tailed species (Carnaby's and Baudin's black cockatoos), together with the yellow-tailed black cockatoo (Z. funerea) of eastern Australia, form the genus Zanda. The two red-tailed species, red-tailed black cockatoo (C. banksii) and glossy black cockatoo (C. lathami), form the genus Calyptorhynchus. The three species of Zanda were formerly included in Calyptorhynchus (and still are by some authorities), but are now widely placed in a genus of their own due to a deep genetic divergence between the two groups. The two genera differ in tail colour, head pattern, juvenile food begging calls and the degree of sexual dimorphism. Males and females of Calyptorhynchus sensu stricto differ markedly in appearance, whereas those of Zanda have similar plumage. The three species of the genus Zanda have been variously considered as two, then as a single species for many years. During the 1970s, Australian ornithologist Denis Saunders analysed the two white-tailed taxa and found that Baudin's black cockatoo also has a longer wing, and wider and higher skull than Carnaby's black cockatoo. Furthermore, there was no overlap in the range of (bill) lengths. In a 1979 paper, Saunders highlighted the similarity between the short-billed and the southern race xanthanotus of the yellow-tailed and treated them as a single species with the long-billed as a distinct species. He proposed that Western Australia had been colonised on two separate occasions, once by a common ancestor of all three forms (which became the long-billed black cockatoo), and later by what has become the short-billed black cockatoo. An analysis of protein allozymes published in 1984 revealed the two Western Australian forms to be more closely related to each other than to the yellow-tailed, and the consensus since then has been to treat them as three separate species. The two white-tailed cockatoo species were called short-billed and long-billed black cockatoos in scientific works, yet they were called Carnaby's and Baudin's black cockatoo in Western Australia. Hence ornithologists Les Christidis and Walter Boles pushed for the latter two names to be used. The International Ornithologists' Union has taken up this suggestion and uses these names as their official common names. The local Noongar people did not distinguish between Carnaby's and Baudin's black cockatoos. Nyungar names recorded include ngolyenok and ngoolyoo (from Northampton). ==Description==

Carnaby's black cockatoo is in length with a wingspan, and weighs 520–790 grams. It is mostly greyish black, with narrow light grey scalloping produced by narrow off white margins at the tips of dark feathers. The scalloping is more prominent on the neck. It has a crest of long feathers on its head that form a short crest that can be raised and lowered, and a prominent off-white patch of feathers on its cheek. Its lateral tail feathers are white with black tips, and the central tail feathers all black. The irises are dark brown and the legs brown-grey. Its beak is shorter and broader than that of the closely related and similar Baudin's black cockatoo; the two are often difficult to distinguish in the field. The adult male has a dark grey beak and pink eye-rings. The adult female has a bone-coloured beak, grey eye-rings and ear patches that are whiter and more distinctive than those of the male. The feathers of its underparts and underwing coverts have larger white margins than those of the male, leading to a more barred or scalloped pattern to its plumage. Its legs and feet are a little lighter than those of the male. Moulting appears to take place in stages in late summer—some time between January or February and April or May, and is poorly understood. Juveniles have a bone-coloured beak, grey eye-rings, and less white in the tail feathers. They can also be distinguished by their constant begging calls. It is not possible to tell the sexes apart until the male's bill begins to darken. This begins when the male is around one year old, and is complete some time after two years of age. ==Distribution and habitat==

Carnaby's black cockatoo is found across a broad swathe of southwest Australia—mostly within the Wheatbelt region—in places that receive over of rainfall yearly. The limits of its range include Cape Arid to the east, Lake Cronin, Hatters Hill and Lake Moore inland, and Kalbarri to the north. Breeding takes place in areas receiving rainfall a year, from the Stirling Range to Three Springs as well as around Bunbury. The cockatoo pairs form flocks outside the breeding season, moving away from nesting areas. Carnaby's black cockatoo is sedentary in wetter parts of its range, and migratory in drier areas as birds move south and west towards the coast in summer. Carnaby's black cockatoo is found in Eucalyptus woodland, most commonly of wandoo (Eucalyptus wandoo) or salmon gum (E. salmonophloia). It is also found nearby pine plantations and sandplains or kwongan heath with abundant Hakea, Banksia, and Grevillea shrubs. ==Behaviour==

Carnaby's black cockatoo communicates by auditory and visual displays. However, in October 2021, a male individual was discovered to be alive and still nesting at the age of 35, having first been tagged in 1986. The bird was discovered six kilometres from where it had been originally tagged. Mature wandoo and salmon gum woodlands provide important breeding habitat for the cockatoos as they need large hollows in tall trees. The nests are generally located about above the ground, and spaced away from each other, on average. There is competition for nest hollows with western corellas (Cacatua pastinator), galahs (Eolophus roseicapilla), and feral honeybees (Apis mellifera). Galahs seek out hollows at any time of year, unlike the Carnaby's black cockatoos, which only look before breeding. Breeding season is from late winter to summer. The female lays a clutch of one or two white eggs, with the second egg laid eight days after the first. One egg is generally larger in a two-egg clutch, and does not differ in size from the egg of a single-egg clutch. It ranges from around long and in diameter. The second egg is around 3 mm shorter. The egg has been calculated to weigh around 33 g, which is 5% of that of the adult female. The second chick usually perishes within the first two days of life; only a small number fledge successfully. The nestlings are usually fed by both parents, with the chicks fledging ten to eleven weeks after hatching. The chicks usually remain in the company of their parents till at least the next breeding season or even longer. The family leaves the vicinity of the nest until they return to breed the following season. Feeding The cockatoo feeds primarily on seeds of proteaceous plants such as Banksia, Hakea and Grevillea, and secondarily on seeds from myrtaceous plants such as Eucalyptus and Corymbia. Over fifty native plant species are commonly used for food, either as seed or flowers, and this includes western sheoak (Allocasuarina fraseriana), orange wattle (Acacia saligna), and balga (Xanthorrhoea preissii). The Swan Coastal Plain north of Perth has become an important feeding area. There, cockatoos also forage in the Gnangara pine plantations, where they feed on the seeds of Monterey pine (Pinus radiata) and maritime pine (Pinus pinaster). Carnaby's black cockatoos have come to depend on these plantations since the early 20th century. ==Predators and parasites==

The wedge-tailed eagle (Aquila audax) kills Carnaby's black cockatoos sporadically, and is the only natural predator of the adult cockatoo. In captivity, it is also susceptible to nematodes of the genus Ascaris if it is in a cage with open dirt flooring. ==Status and conservation==

The cockatoo is recognised as endangered under the federal Environment Protection and Biodiversity Conservation Act 1999, The bird is part of an annual census, the Great Cocky count, that has been held every year since 2009 to track the population change of Carnaby's and other black cockatoos. The 2016 Great Cocky Count counted 10,919 Carnaby's black cockatoos, indicating the population had declined by 50% on the Perth–Peel Coastal Plain since 2010, dropping by around 10% each year. The total population is estimated to consist of 40,000 individuals. Major threats to the cockatoo include clearance of their feeding and nesting habitat, destruction of nesting hollows (e.g. during firewood collection), competition with other species for nest sites, and poaching. Much of this area lies within the Perth metropolitan area, and the city's population is predicted to increase 70% by 2050. The Western Australian State Government has produced a Green Growth Plan to manage this expansion; conservation groups are concerned the cockatoo (along with other species) could suffer further loss of habitat. In particular, the loss of pine plantations north of Perth could jeopardise the species' food supply. In February 2017, WWF-Australia and BirdLife Australia appealed to the Federal Environment Minister Josh Frydenberg to intervene and halt the ongoing removal of pine trees. BirdLife International designated 13 sites (Important Bird Areas) as being important specifically for Carnaby's black cockatoo. These are the Northern Swan Coastal Plain, which supports between 4600 and 15000 birds outside the breeding season, the Stirling Range, and 11 other sites that support between 20 and 110 breeding pairs of Carnaby's black cockatoos. The cockatoos fly into open space when leaving the vegetation, which is often over a road and in the path of oncoming traffic. Like most species of parrots, Carnaby's black cockatoo is protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) with its placement on the Appendix II list of vulnerable species, which makes the import, export, and trade of listed wild-caught animals illegal. ==Notes==