Helmeted cockatoo

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Helmeted cockatoo
Crested Cockatoos, a male on the left

Crested Cockatoos, a male on the left

Systematics
Class : Birds (aves)
Order : Parrots (Psittaciformes)
Family : Cockatoos (Cacatuidae)
Genre : Helmeted cockatoos
Type : Helmeted cockatoo
Scientific name of the  genus
Callocephalon
Lesson , 1837
Scientific name of the  species
Callocephalon fimbriatum
( Grant , 1803)
Distribution of the cockatoo in the southeast of Australia

The helmet Kakadu ( Callocephalon fimbriatum ) is an Australian parrot bird that is circulated only in the southeast of the Australian continent. The distribution center of the cockatoo is thus in one of the most densely populated regions of Australia. During the Australian summer, the cockatoo is mostly in mountain forests. It also settles at high altitudes that have daytime temperatures of ± 0 degrees in July. During the winter months, cockatoos often migrate to valleys and coastal plains and then also occur in the catchment area of ​​cities, where they prefer to eat the cones of pine trees that are cultivated as ornamental plants.

It is the only representative of the helmet cockatoo genus and no subspecies are distinguished. The unusual spring bonnet is characteristic of this species. This is bent forward and formed by soft, filamentous feathers. Beak is very massive. There is a deep notch on the lower beak. The tail feathers are short and angular. The wings, however, are long and almost reach the tail end. There is a striking gender dimorphism. Only in the male are forehead, head, bonnet, reins, eyes and cheek regions bright red plumage.

Appearance

Helmet cockatoos reach a body length of 35 centimeters and weigh between 210 and 340 grams. Helmet cockatoos have dark gray body plumage. The individual feathers have a gray-white border, so that the cockatoo looks scaled overall. This feather hem on the underside of the body is particularly noticeable. There the feather hem occasionally turns yellowish to orange. The beak is broad and very strong. The wings are rounded and long in relation to the body size. The legs of this tree-dwelling cockatoo species are short and stocky. The tail is relatively short.

In the males forehead, crown and neck, the reins and the upper cheek regions up to the ear cover are bright orange-red. The outside of the arm covers have a dull green sheen. The tail is dark gray and becomes even darker towards the tip of the tail. The beak is horn-colored and turns gray towards the base of the beak. The iris is dark brown.

The females largely resemble the males. Their hood and head plumage are gray. Only older females occasionally have single feathers on the forehead and crown that are orange-red in color. On the underside of the body, the feathers have a clearly orange-colored border. There is a strong, greenish-yellow horizontal stripe on the underside of the tail. The tail is gray and, depending on the individual, has different stripes from pale gray to white. The beak is slightly paler than that of the male. Young birds initially resemble females. However, male juveniles show red feathers in the area of ​​the head and hood very early.

Helmet cockatoos are very powerful fliers that are able to cover long distances at high altitudes. However, they are characterized by a short flight from tree to tree. The wing beats are slow and propulsive. During short flights between two trees, they can first slide down to regain altitude shortly before touchdown.

distribution and habitat

Cockatoos occur in southeastern Australia from east New South Wales across the east and south of the Australian state of Victoria to the extreme southeast of South Australia . They used to be widespread on King Island and also came to the north of Tasmania as random visitors . They were introduced on Kangaroo Island off the south coast of Australia in 1947 and a second time in 1957. You have established yourself there. However, the stock is considered to be in decline.

Crested Cockatoos are found in the temperate climates of southern Australia and mainly inhabit forests. In the northern and therefore warmer part of their range, they are mainly in the highlands. In the Snowy Mountains they occasionally reach an altitude of up to 2200 meters above sea level. In the cooler south, they are also common in lowland forests. During the summer months they prefer to stay in cooler valleys. During the winter they are also found on drier, more open tree savannahs. Like many other cockatoo species, they also use urban habitats. So are occasionally seen in the suburbs of Sydney , Canberra and Melbourne .

Crested cockatoos do not show any uniform migration behavior. Some are resident birds, some migratory birds with regular seasonal migrations, and other populations nomadic undirected. It seems to be an adaptation to the respective climatic conditions of their habitat as well as the available food supply.

Behavior and food

Outside the breeding season, cockatoos live in small flocks. Larger swarms with sixty or more individuals occur in special places such as water holes or places with particularly abundant food. Cockatoos prefer to stay in trees and usually only go to the ground to drink. During the hottest time of the day, they usually sit in the shade in the foliage of trees. They either spend this time motionless or do intensive plumage care with their partner. When it rains or even when it is snowing, however, they often fly around in circular orbits above the treetops.

Crested Cockatoos feed on the seeds of various plants. Eucalyptus are of great importance in the food spectrum , of which 22 different species occur in the range of the cockatoo. Besides playing acacia , Pyracantha and Crataegus a role. They also eat berries, nuts, fruits, green plant material and, to a lesser extent, insects and their larvae. They also like to eat imported plants such as the fruit of the firethorn . When eating, the birds bite off branches with seeds and fruit bunches and hold them with one foot. Individual seeds are picked from the seed pods with their beak. The ornithologist Joseph M. Forshaw , who specializes in Australian parrots, describes the helmeted cockatoos as the Australian parrot species that possesses the most advanced foot-holding technique. Food intake takes a very long time in the daily routine, as most of the types of food consumed are very hard-shelled and small in size.

Reproduction

female

The nesting season of the cockatoos is in eastern Victoria and southern New South Wales from October to January. As with many cockatoos, the courtship repertoire is relatively simple. The male calls for the female with a spread hood and in a tense posture. It spreads its wings.

Cockatoos are cave breeders. The preferred nesting tree is found on the slopes of mountain valleys near watercourses. They often use their nesting holes for several years in a row. The nest cavity is primarily chosen by the female. The male sits nearby and calls softly interrupted while they keep raising their red hood. At the bottom of the nest box there are only bits of wood and wooden mole. The clutch usually consists of two, more rarely three eggs. The incubation period is 30 days. Both sexes breed, with the female usually breeding at night and the male during the day. Partner feeding during the breeding season has not yet been observed.

Newly hatched nestlings are sparsely covered with yellow dunes. The first contour feathers become visible between the second and third week of life. During this period, the eyes open for the first time. The young birds leave the nest box for the first time when they are 47 to 50 days old. The young birds are then looked after by the parent birds for two to three months.

Helmeted cockatoos and human

Since Australia issued an export ban on all domestic animal species in the second half of the 20th century, specimens have only very rarely made it to Europe or North America. Helmet cockatoos are accordingly traded at very high prices. Successful cockatoo breeds are still very rare. The world's first breeding took place in France in 1921.

Helmet cockatoos are demanding fosterlings who can only be kept in pairs in large aviaries for their well-being. They show a very pronounced tendency to pluck feathers. This behavior can be triggered by heat stress or boredom. They have a very strong gnaw drive and resist treatment with energetic bites. This can lead to severe bite wounds on the holder. Since cockatoos spend a lot of time foraging for food in the wild, successful owners employ ripe and semi-ripe pine cones, leafy willow twigs and even offer them bones to keep them from their tendency to pluck feathers.

supporting documents

Individual evidence

  1. ↑ Hoppe, p. 109.
  2. ^ Forshaw, p. 140.
  3. ↑ Hoppe, p. 108.
  4. ^ Forshaw, p. 145.
  5. ^ Forshaw, p. 141.
  6. ↑ Hoppe, p. 109.
  7. ^ Forshaw, p. 141.
  8. ^ Forshaw, p. 144.
  9. ^ Forshaw, p. 144.
  10. ↑ Hoppe, p. 110.
  11. ^ Forshaw, p. 145.
  12. ↑ Hoppe, p. 110.
  13. ^ Forshaw, p. 146
  14. ↑ Hoppe, p. 109.
  15. ↑ Hoppe, p. 110.
  16. ^ Forshaw, p. 146.
  17. ↑ Hoppe, p. 111.

literature

Web links

Commons : Great-horned Cockatoo ( Callocephalon fimbriatum )  - Collection of images, videos and audio files