Root cockatoo
| Root cockatoo | ||||||||||
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Root cockatoo |
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| Cacatua pastinator | ||||||||||
| ( Gould , 1841) |
The root cockatoo ( Cacatua pastinator ), also known as the western long-billed cockatoo , is a species of parrot native to Australia. Root cockatoos , along with the bare-eyed cockatoos and the nasal cockatoos, belong to the so-called "Corellas". It is a very rare species with an unusually small range. Root cockatoos occur with two subspecies only in the southwest of Australia. In 1985 it was estimated the population of the root cockatoo at 3,000 specimens. Meanwhile the population has recovered to 5,000 to 10,000 birds. The species is still considered endangered because the total population is now only small, the reproduction rate is low and it is also endangered by the huntings by farmers. In Australia, the root cockatoo is protected by law.
Appearance
Root cockatoos reach a body length of 45 centimeters and weigh between 700 and 860 grams.
The basic color of the plumage is white. Root cockatoos have only a small feather hood, which consists of the front, elongated crown feathers. The reins are orange. The bases of the feathers on the head, front back, chest and flanks are pinkish-orange. The bases of the feathers on the upper and lower wing coverts are pale yellow. The flight springs and the outer control springs are white. However, they are yellow at their base, as well as on the inner lugs on the bottom. The beak is horn-colored. Similar to the nasal cockatoo, the upper bill is elongated. The iris is dark brown. The bare eye region is striking. It is greyish-blue and, similar to the bare-eyed cockatoo, somewhat extended below the eye.
The flight of the burrowing cockatoo consists of fast, flat wing beats, which are interrupted by short gliding phases. Root cockatoos that fly long distances do so at high altitudes. When they get to their destination, they slide down in wide circles without moving their wings. Only shortly after landing on the ground or in the treetops do they flap their wings again.
Similar to the nasal cockatoos, the contact call of the root cockatoos is three-syllable. Their calls are particularly loud when they leave for the food grounds in the morning or when they come to their sleeping trees in the evening.
Distribution, habitat and population development
Root cockatoos are found only in southwest Australia. The natural habitat of this species are tree savannas and open valleys within forests.
The species was still considered numerous around 1830. Large flocks of burrowing cockatoos occasionally raided the fields near Perth. They were persecuted very badly. It was common practice to exterminate the large swarms with the help of poisoned grains. This practice has resulted in the complete extinction of the root cockatoos in some regions.
Root cockatoos are now fully protected. Their number has recovered slightly in recent decades. However, they are still endangered because the total population is very small. The problem is that the remaining population comes together in relatively few swarms after the breeding period. This makes them particularly vulnerable to (now illegal) stalking by farmers.
food
Root cockatoos mainly feed on the ground. With their elongated upper beak, they are able to dig in the ground and thus also reach subterranean plant parts. Much of their diet now comes from plants introduced in Australia . In addition, they eat grass seeds, seeds of herbaceous plants, nuts, fruits, berries, buds, flowers as well as insects and their larvae. In the Wheatbelt Region , a heavily developed agricultural area in Western Australia, wheat is also important for their diet. A large part of the conflicts with farmers result from this. They eat freshly germinated wheat seeds as well as young saplings. They plunder ripe ears of wheat by bending down the wheat plant, holding onto the ground with their feet and picking the grains of wheat from the ear with their beak. Animal diet plays a role especially during the breeding season.
Reproduction
Root cockatoos are monogamous birds. Once a partnership has entered into, it usually only ends when one of the partners dies. Pairing takes place in the flocks of immature birds in which the cockatoos live after they have become independent. Females appear to form pair bonds in their second year of life. However, the first attempt at breeding is only made between the ages of four and five.
Root cockatoos are cave breeders. Eucalyptus trees are the preferred breeding tree . The eggs are pear-shaped to elliptically oval. The clutch consists of two to four eggs. On average, a clutch contains 2.7 eggs. Both parent birds breed. The incubation period is 22 to 23 days. Newly hatched nestlings are a week brooded . The huddling is reduced up to the 25th day of life of the young birds. The young birds leave the breeding cave at around 60 days. The young birds are initially fed by the parent birds for a while.
The reproduction rate is very low. This also explains why pink cockatoos in Western Australia spread faster and more sustainably than root cockatoos. On average, only 1.6 young birds survive the nestling period. A couple who first breed both birds in their third year of life must reach 5.4 years of age to even replace themselves.
supporting documents
Individual evidence
- ^ Forshaw, p. 211.
- ^ Forshaw, p. 211.
- ^ Forshaw, p. 215.
- ^ Forshaw, p. 213.
- ^ Forshaw, p. 216.
- ^ Forshaw, p. 216.
- ^ Forshaw, p. 219.
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 0195530713 .
Web links
- Cacatua pastinator inthe IUCN Red List of Endangered Species 2013.1. Listed by: BirdLife International, 2012. Retrieved September 3, 2013.