Carnaby's white-eared black cockatoo
| Carnaby's white-eared black cockatoo | ||||||||||
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Carnaby's white-eared black cockatoo |
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| Calyptorhynchus latirostris | ||||||||||
| Carnaby , 1948 |
Carnaby's white-eared black cockatoo ( Calyptorhynchus latirostris ), also known as the white-tailed black cockatoo , is a species of parrot found in Australia. The species belongs to the black cockatoo genus . Although they can also be observed in the urban area of Perth , Carnaby's white-eared black cockatoo is a relatively rare species. Extensive tree clearing in the range of the species has contributed to the decline in the population of this species. Carnaby's white-eared black cockatoos, as cave breeders, are dependent on sufficiently old trees. The distribution area of this cockatoo is in the so-called wheat belt , an intensively agriculturally used part in the southwest of Australia.
Carnaby's white-eared black cockatoos are diurnal parrots that leave their sleeping trees shortly after the start of the day and fly into their feeding grounds. They rest in trees during lunchtime and only show a second peak of activity in the afternoon. They feed primarily on seeds and prefer those of the silver tree plants and screw trees . But they also eat the seeds of the pine trees that were introduced into Australia. Their food spectrum also includes fruits, flowers, buds and insect larvae.
Appearance
Carnaby's white-eared black cockatoo reach a body length of about 55 centimeters and weigh between 540 and 790 grams. The plumage is gray-black, with the underside of the body being a little more dull and brown in color, especially in the rear area of the body. The body feathers are narrowly lined with gray and white, which gives the bird a scaly appearance. The gray and white ear covers give it its name. As with many other black cockatoos, Carnaby's white-eared black cockatoo has a cross-band in the rear half of the outer control feathers. This is white in Carnaby's white-eared black cockatoo.
The males of Carnaby's white-eared black cockatoos have a strong, gray-black bill, a dark brown iris and a pink-flesh-colored eye ring. In females, the beak is horn-colored and only the tip is gray-black. The eye ring is gray. The white ear covers are slightly larger and less clearly delimited from the rest of the head plumage. Fledglings resemble adult females. The easiest way to identify them is by their regularly repeated rough begging calls and the smooth surface of their beak. Males not yet sexually mature have a dark upper bill, while the lower bill is still horn-colored.
It can be confused with the Baudin's white-eared black cockatoo . The distribution area of both species overlaps slightly and both have white ear covers and a white cross band on the outer tail feathers. Carnaby's white-eared black cockatoo, however, has a wider beak with a more blunt tip of the upper beak. However, this can only be clearly recognized if one can approach the cockatoo accordingly. The only other cockatoo with dark plumage that occurs in Western Australia is the Banks Black Cockatoo - however, this has a red or yellow cross-band on the tail feathers depending on its gender.
Distribution area and habitat
Carnaby's white-eared black cockatoos are found only in the extreme southwest of Australia. Their breeding area is largely allopatric with Baudin's white-eared black cockatoo. Their respective area of distribution is largely separated from one another by the 750 mm annual isohyte . Carnaby's white-eared black cockatoo is a breeding bird in the so-called wheat belt of Australia. In regions with a rich food supply, Carnaby's white-eared black cockatoos are resident birds. In the eastern areas and in the regions of their range with less precipitation, however, they are migratory birds that migrate to the coastal area in the Australian summer months.
The habitat of Carnaby's white-eared black cockatoos are semi-arid shrub savannahs with silver tree plants and shrub heather. At the edge of these savannahs there must be stands with sufficiently old trees of the eucalyptus species Eucalyptus wandoo and Eucalyptus salmonophloia . Outside of the breeding season, they also stay in slightly more rainy forested regions in the southwest and during this time they overlap with the range of Baudin's white-eared black cockatoo. In this region, however, there are no tree species that Carnaby's white-eared black cockatoo uses as a breeding tree. Basically, however, the Carnaby's white-eared black cockatoo uses drier forests and bushland than the Baudin's white-eared black cockatoo.
Carnaby's white-eared black cockatoos can also be seen in plantations of the pine trees introduced into Australia. They can be found in gardens, parks, on agricultural land and fruit-growing areas.
behavior
Carnaby's white-eared black cockatoos are sociable birds. They can usually be seen in groups of at least three birds, and occasionally in flocks of several hundred individuals. Wherever there is plenty of food, it is occasionally associated with the Banks Black Cockatoo and the Baudin's Black-eared Black Cockatoo. Adult birds are usually not very vocal when foraging for food, whereas the still dependent young birds are very happy to call.
While foraging for food, they mostly stay in the treetops, but they often come to the ground to look for food. Your movement on the ground looks awkwardly waddling. Their flight, on the other hand, is lively and majestic with slow, sweeping wing beats, which are interrupted by longer gliding flights. When they change their feeding grounds, they usually fly high above the treetops. Before settling in a tree, they usually circle over the top of the tree. When landing, Carnaby's white-eared black cockatoos spread the control feathers and the hood.
Duration
Carnaby's white-eared black cockatoo populations are declining. Extensive tree felling occurred in the breeding area of this species, as this region is used intensively for agriculture. About a third of the breeding area no longer has suitable habitats for this species. The increasing destruction of suitable breeding trees means that the breeding population is concentrated on increasingly few remaining forest remnants. The destruction of the shrub heather around these remaining forest stands means that breeding birds cannot find sufficient food and the reproduction rate declines. The ornithologist Joseph M. Forshaw , who specializes in the Australian parrots, doubts the validity of population numbers, but rather attaches the decline in the species to the declining flock size: Up to the beginning of the 1970s, flocks of Carnaby's white-eared black-tailed cockatoos were regularly observed, up to Comprised 5,000 individuals. At the beginning of the 21st century, swarms with 1,000 individuals are a rarity. Swarms larger than 2,500 individuals are no longer observed. He also points to studies showing different rates of reproduction between breeding pairs in largely untouched habitats and those that breed in island-like eucalyptus forests in agricultural regions. The former have a reproductive rate of 0.6 young birds per year and pair. The latter, on the other hand, only out of 0.3 young birds. He sees the significantly poorer food supply as the main cause.
In contrast, human interventions in the habitat of Carnaby's white-eared black cockatoo have promoted the spread of the pink cockatoo and the naked-eye cockatoo . Both species compete with Carnaby's white-eared black cockatoo for nesting holes, although they are significantly smaller.
Reproduction
Carnaby's white-eared black cockatoos live in large flocks outside of the breeding season. They can also be observed in swarms during the breeding season, but they are much smaller during this time. However, couples never move far apart, even in flocks. The couple bond is considered close and long-term. Mated males can only be observed alone during the time when the females are breeding or the young are breeding.
The courtship repertoire of Carnaby's white-eared black cockatoos is not very large. The male's impressive appearance is striking. He walks with a raised hood and fanned out control springs in a tense posture towards the female and then bows to her. The start of the breeding season falls in the months of July to September. Couples who have left their breeding area and are returning at this point start choosing a breeding cave immediately after their return. Disputes with conspecifics only arise when there is competition for breeding caves. Occasionally, there are brief fights.
Carnaby's white-eared black cockatoos build their nesting holes in dead and living eucalyptus trees. They use every eucalyptus species, but usually prefer the predominant species. The clutch consists of one or two eggs. The laying interval between the two eggs is eight days on average. As a rule, only one nestling grows up in clutches with two eggs. The smaller and weaker nestling is usually so neglected by the parent birds that it dies within a short time. In an examination of 222 nests with two eggs, both nestlings were raised in only eight cases.
The eggs are incubated by the female alone. The incubation period is 29 days. Young Carnaby's white-eared black cockatoos usually leave the breeding cave after 80 days. They are independent at around 7 months, but usually form a closer family group with the parent birds until the next breeding season.
food
During the breeding season, Carnaby's white-eared black cockatoos mainly use native plants as a source of food. Silver tree plants are their most important source of food during this time. They also eat herons' beaks that grow in pastures, roadsides and railways. Outside of the breeding season, they often look for food in pine plantations and occasionally also in almond plantations. They do not use wheat fields as a source of food.
Carnaby's white-eared black cockatoos and human
Australia prohibits the export of wild animals to other countries. Carnaby's white-eared black cockatoos are therefore very rare pets outside of Australia. They are also kept relatively rarely in Australia. They are now regularly bred and there is a conservation program in Australia in which the second egg or the second young bird is removed from the nests under strict conditions and given to keepers who build an aviary population with these birds. This cockatoo is demanding to keep and needs very large aviaries.
supporting documents
Individual evidence
- ^ Forshaw, p. 89.
- ^ Forshaw, p. 82.
- ^ Forshaw, p. 82.
- ↑ Higgins, p. 79.
- ↑ Higgins, p. 79.
- ↑ Higgins, p. 78.
- ^ Forshaw, p. 95.
- ↑ Higgins, p. 79.
- ^ Forshaw, p. 82.
- ^ Forshaw, p. 87.
- ^ Forshaw, p. 84
- ↑ Higgins, p. 79.
- ↑ Higgins, p. 79.
- ^ Forshaw, p. 85.
- ↑ Higgins, p. 79.
- ^ Forshaw, p. 85.
- ^ Forshaw, p. 85.
- ^ Forshaw, p. 90
- ^ Forshaw, p. 91.
- ↑ Higgins, p. 79.
- ^ Forshaw. P. 91.
- ^ Forshaw, p. 91.
- ↑ Higgins, p. 79.
- ^ Forshaw, p. 86.
literature
- Joseph M. Forshaw , illustrated by William T. Cooper: Australian Parrots. 1st German-language edition. Volume 1: Cockatoos and Lories. Arndt-Verlag, Bretten 2003, ISBN 978-3-9808245-1-4 .
- PJ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Bird. Volume 4: Parrots to Dollarbird. Oxford University Press, Oxford 1999, ISBN 0-19-553071-3 .
Web links
- Zanda latirostris inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2013. Retrieved December 26, 2013.