Hornbill

from Wikipedia, the free encyclopedia
Hornbill
Wrinkled hornbill (Aceros corrugatus), male with cervical plumage, which is colored orange by the rump secretion

Wrinkled hornbill ( Aceros corrugatus ), male with cervical plumage, which is colored orange by the rump secretion

Systematics
Class : Birds (aves)
Order : Hornbills and hops (Bucerotiformes)
Family : Hornbills (Bucerotidae)
Genre : Aceros
Type : Hornbill
Scientific name
Aceros corrugatus
( Temminck , 1832)
Head study of a male
In this male, the neck plumage is not colored by the rump secretion and shows the original white

The wrinkled hornbill ( Aceros corrugatus ) is a medium-sized representative of the hornbill (Bucerotidae). It breeds in Malaysia and Indonesia . Like all hornbill species, the wrinkled hornbill is a cave breeder. The female walled herself up to a narrow gap in a natural tree cavity during the breeding season. The male provides them and later the young birds with food.

In 2016, the Red List of Threatened Species of the IUCN classified the wild hornbill's population as " Near Threatened (NT) " = "potentially endangered".

Appearance

The wrinkled horn bird reaches a body length of 65 to 70 centimeters. The tail feathers account for an average of 27.1 centimeters in males and 23.3 centimeters in females. The males have a beak between 16.8 and 20.5 centimeters. The female's beak remains slightly smaller and is 14.4 to 15.0 centimeters in length. The weight is between 1400 and 1600 grams. There is a noticeable gender dimorphism .

Appearance of the male

The male has a black crown, a black rear neck, black body plumage and black flights. On the upper side of the body, the plumage has a metallic green sheen. The tail feathers have a black base and freshly molted white ends. The face and the front neck are white. The rump secretion with which the wrinkled hornbill takes care of its plumage has an intense yellow-red color. Due to the plumage care, the white plumage areas are colored yellow-orange. The beak has a red base and is yellow in the front half. The beak attachment is deep red. The beak and horn attachment are also colored red by the rump secretion.

The featherless skin around the eye is blue, the very large and elastic throat pouch is light yellow. The eyes are red, the feet and legs are black.

Appearance of the female and young birds

The female is smaller than the male and her beak horn is less developed. The face and fore neck are black. The beak is pale yellow with a brown beak base. The featherless skin around the eye is blue. The bare throat patch is also bluish. The eyes are gray-brown, the legs and feet are greenish gray.

In young birds, both sexes initially have a body plumage that resembles the adult male. The beak is pale yellow with an orange tinge at the base of the beak. Some individuals have a black spot on the lower beak. The beak horn is not yet developed. The featherless skin of the face is pale yellow. The eyes are yellow-brownish. The legs and feet are blue-gray.

In the wild, the subadult females develop the black face and neck plumage typical of females at around one year of age. The development of the Schnabelhorn takes several years. In older males, the beak horn has grooves.

Subspecies

Occasionally, two subspecies are described for the curled hornbill.

  • Aceros corrugatus corrugatus (Temminck, 1832): Indochina, Malaysia, Brunei, Indonesia
  • Aceros corrugatus rugosus (Begbie, 1834): Indochina, Thailand, Malaysia, Indonesia, Sumatra

Allen Kemp points out that the distinction is essentially based on the size difference, since the individuals of this species are slightly smaller in the southeast of their range. Such a shift in size can, however, also be observed in other hornbill species and therefore possibly only represents a cline , a continuous change in a feature along a geographical line.

Possible confusion

The males with their high beak horns and yellow-red bills and the females with their blue throat pouches are almost unmistakable in the wild. The greatest similarity with the Runzelhornvögeln, the occurring in the same habitat furrows hornbill on. This is significantly larger than the curled hornbill, has an exclusively white tail, no beak horn, but only a slightly raised beak ridge and the facial skin is yellow and red.

distribution and habitat

Distribution area of ​​the wrinkled horn bird

Wrinkled hornbills are common in much of Southeast Asia. Its range includes Malaysia, Brunei, Indonesia, the extreme south of Thailand, Sumatra and Borneo. They also colonize some of the smaller islands that border Sumatra. These include Rupat , Payong and the Batu Islands . The hornbill is rare in large parts of its distribution area. In Thailand the hornbill is threatened with extinction and this species is also very rare on the Malay Peninsula. In contrast, the hornbill is still relatively common in the south of Sumatra and in parts of Borneo.

The habitat of the wrinkled horn bird are dense tropical rainforests of the lowlands. Outside the breeding season, it roams a very large area.

Way of life

Wrinkled hornbills usually live in pairs or in small family groups consisting of three birds. Occasionally, groups of up to 30 individuals also form. Wrinkled horned birds show little antagonistic behavior within these flocks, but mated birds often stay close together. When changing to another troop of wrinkled hornbills, this also usually happens in pairs. Subadult wrinkled hornbills usually form their own flocks. Behaviors that contribute to pairing can be observed in these squads. This includes courtship feeding. Birds of a flock rest near each other at night. They look for food places together. There can be a distance of up to ten kilometers between the resting place and the area where food is sought. On these flights, they cross forest areas at a higher altitude.

nutrition

Depiction of a female from 1838

Wrinkled hornbills find their food mainly in the canopy area of ​​large trees. They prefer to choose trees with a crown that towers above the neighboring trees. You can quickly switch between the individual trees. Because of their fried wings and long tail feathers, they are so skillful that they are able to pick up fruit from the branches in flight.

Wrinkled hornbills, like most hornbills, are omnivorous. They cover their nutritional needs for the most part with fruits. Figs play a less important role in their diet than most Asian hornbills. They only make up about 20 percent of the diet. Lipid-rich stone fruits and capsule fruits play a bigger role in their diet . A large number of eaten fruits and seeds come from plants that belong to the laurel and balsm tree family . With its beak, the hornbill is able to open hard-shelled capsule fruits. This is particularly important when the food supply is scarce.

The hornbill interrupts the search for vegetable food again and again by hunting small vertebrates and arthropods. It is one of the species that has been observed to catch smaller species of birds.

Reproduction

The reproductive biology of the wrinkled horn bird has not yet been conclusively investigated in the wild. Most of the knowledge was gained from individuals cared for in human care.

The wrinkled rhinoceros reach sexual maturity at around four years of age. The breeding season on Borneo falls between January and May. The food supply seems to play a significant role in whether hornbills brood at all. Clutches can contain up to three eggs. With wrinkled hornbills kept in captivity, however, this third egg was often not incubated or the nestling was considerably slower in growth.

Tree cavities at great heights serve as breeding caves for the couples. It is not uncommon for the caves in the upper tree regions to be more than 30 meters above the forest floor. The nesting site is prepared exclusively by the female. The female usually lays two, rarely three eggs, of which rarely more than one young survives after hatching. Once the female has laid the eggs, something unique happens in the bird world. The female builds up the entire brood cavity from a mixture of food, pieces of wood and excrement, which is processed into a pulp. This can only be observed in the hornbill family (Bucerotidae). The male also brings mud to his female, which is also processed. Only a narrow gap remains open. Through this opening, the brood and the female are supplied with food by the male. The chicks hatch after around 30 days. The chicks are initially naked and blind. After the young birds have fledged between 65 and 70 days of age, the female opens the nest cavity. She is hammering the masonry with her beak. The life expectancy of the wrinkled hornbill is unknown, but it is thought to be around 20 years.

Hazard and protection

In large parts of its distribution areas, the hornbill is still relatively common. In some regions, however, they have already completely disappeared or are threatened with extinction. Especially in regions where the destruction of the rainforests is progressing at breakneck speed, things are more than bad for the wrinkled hornbills. Wrinkled hornbills can only live in tropical rainforests, as this is the only place where they can find enough food and nesting opportunities. In Malaysia and Thailand the species is on the verge of extinction. Another problem is the hunting of birds and capturing them in the wild for the pet trade.

Hornbill and man

Wrinkled hornbills are occasionally shown in zoological gardens. The first captive rearing took place in 1988.

literature

Web links

Commons : Hornbill  - Collection of images, videos and audio files

Single receipts

  1. ↑ Rhabdotorrhinus corrugatus in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Retrieved on 3 October 2017th
  2. ↑ Kemp: The Hornbills - Bucerotiformes . P. 219.
  3. ↑ a b c Kemp: The Hornbills - Bucerotiformes . P. 218.
  4. ↑ a b c d e f Kemp: The Hornbills - Bucerotiformes . P. 220.