Banksian black cockatoo, Banks' black cockatoo
Red-tailed black cockatoos are 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. 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.
Red-tailed black cockatoos occur in Australia and are more widespread in the northern drier parts of the continent. They are not wholly migratory, but they do exhibit regular seasonal movements in different parts of Australia. These birds live in open country as well as forests. They prefer Eucalyptus woodlands and riverside trees but can also live in a wide variety of habitats, including subtropical rainforest, farmland with scattered Eucalyptus, or grasslands with scattered trees.
Red-tailed black cockatoos are diurnal and raucous and are often to be seen flying in small flocks high overhead, sometimes alongside other cockatoos. Flocks as big as 500 are usually seen only in the north or concentrated at a food source. They depart from their communal roost early in the morning to drink at a regular place, then disperse widely to feed. They remain sheltered in the foliage around the middle of the day and return to the feeding areas late in the afternoon. The flock returns to its roosting trees near water at the close of the day. In central and northern Australia, the cockatoo feeds in trees or on the ground. Southern species feed mostly in the trees. These cockatoos are not wholly migratory, but they do exhibit regular seasonal movements in different parts of Australia.
These cockatoos are herbivores (granivores) and eat mainly seeds. However, they will also consume fruits, nuts, bulbs, flowers, and insects. Favorite seeds are eucalypts, acacias, casuarinas, and banksias.
The Red-tailed black cockatoo is monogamous, mating for life. If it happens that one partner disappears, the other may choose not to mate again. Mating takes place usually between May and September except for the south-eastern bird, which nests during the summer (December to February). The cockatoo nests in tree hollows or in dead trees, and they must be tall trees. They line the hollow with decayed and chewed wood. The female lays 1 egg, occasionally 2. Only 1 chick will be raised. Incubation is carried out just by the female, for about 28 to 30 days. The female is fed by the male during incubation. The chick is fed by both parents and depends on its parents for food for about 3 months. It may fledge at about 100 days of age when it has reached adult size. Reproductive maturity is reached within about 4 years.
As with many Australian parrots, the cockatoo is threatened by bird smuggling and is most often observed in captivity. Other threats are habitat modification, clearing for forestry and agriculture or forestry, urban development, and also climate change.
According to IUCN, the Red-tailed black cockatoo population is believed to be in excess of 100,000 individuals. The Northern subspecies of Red-tailed black cockatoo is widespread and is not considered endangered. Just in the Northern Territory, there are about 60,000 birds. The Southeastern subspecies, however, is considered endangered. In 2001 there were estimated to be only 650-1000 birds in the population, including 500-770 adults. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.