Oriental hornbill
| Oriental hornbill | ||||||||||
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Female oriental hornbill of the subspecies Anthracoceros albirostris , Singapore |
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| Anthracoceros albirostris | ||||||||||
| ( Shaw & Nodder , 1807) |
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The oriental hornbill ( Anthracoceros albirostris ), also known as the white helmets hornbill , is a species of the hornbill family that occurs in Southeast Asia. Like all hornbills, the oriental hornbill is also a cave breeder. The female blocks the breeding cavity from the inside except for a narrow gap. The male feeds the female sitting in it and later the young birds through the narrow gap.
There are two subspecies in the large distribution area of the species: The northern hornbill ( Anthracoceros albirostris albirostris ) occurs from India, Nepal and China to Thailand and the northeast of the Malay Peninsula . The Sunda oriental hornbill ( Anthracoceros albirostris convexus ) has its distribution center in Indonesia and lives here on numerous islands.
The population of the oriental hornbill was classified in the IUCN Red List of Threatened Species in 2016 as “ Least Concern (LC) ” = “not endangered”.
description
The oriental hornbill reaches a body length of up to 60 centimeters. The beak of the male of the nominate form Anthracoceros albirostris albirostris reaches a length of 11.3 to 18.7 centimeters. In females, the beak remains slightly smaller at 11 to 15.6 centimeters. Males weigh between 680 and 795 grams, while females weigh between 567 and 680 grams.
Characteristics of the male
The male's head, neck, front chest, back and wings are black and have a greenish tinge. The lower chest, thighs, abdomen and under wing coverts are white. The tail is black with a broad white tip except for the middle pair of tail feathers. The middle pair of tail feathers is black and rises above the other tail feathers by 3 centimeters. Only a few individuals also have a narrow white tip in this middle pair of control springs.
The beak horn is big. The horn begins at the level of the base of the beak and ends at about half the length of the beak. The beak is yellow, the base of the beak is black on both the horn and the beak. The horn has a black to dark tip at the end. Depending on the age, this black coloration can also extend to the beak. The bare skin around the eye is white with a black spot in front of the eye. The bare throat patch is white-bluish. The eyes are dark red, the legs and feet are gray-green.
Features of the female and young birds
The females are similar to the males in terms of body plumage, but are slightly smaller overall. The horn is less convex than in the male, the horn is also not pointed. The bill and horn are yellow. The black to brown coloration on the beak and horn are individually different in the females than in the males. The front half of the beak is often black, however, there are brown spots on the lower bill on the sides and the base of the beak. The eyes are brown to gray-brown.
The body plumage of the young birds is similar to that of the adult, but their control feathers often have more black parts than that of the adulterers. The beak is much smaller, the beak horn not yet developed, and usually completely pale yellow with no further markings. The bare skin around the eye is white with a pink sheen, the throat spot is flesh-colored to blue-white, the eyes are dark brown.
The development of the horn begins in the young birds one to two months after they fledged. By the age of 12 to 13 months the shape is largely developed, but the horn becomes slightly larger after three years of age.
Characteristics of the subspecies Sunda oriental hornbill
The subspecies A. a. Described by Coenraad Jacob Temminck in 1831 . convexus or sunda hornbill resembles the nominate form in the body plumage. However, many individuals have black spots on the white part of the control feathers. This can be observed in 23 percent of the adult oriental hornbills and in 88 percent of the not yet sexually mature individuals of this subspecies. They are also slightly larger. The beak in the males reaches a length of 15.5 to 19.7 centimeters. In females, the beak length varies between 12.4 and 15.3 centimeters. Weight data are only available for a few individuals. The males weighed 907 grams, the females 879 grams.
The beak and the beak horn have the same shape as the nominate form, but the female usually has less black on the beak. However, there are differences between the individual island races in this subspecies. In the males, the black spot in front of the eye is missing. The eye color of both sexes is light cinnamon brown, while the young birds have gray-brown eyes.
voice
The calls of the oriental hornbird are a series of lighter, louder and shrill field sounds. Typical are Kek - Kek - Kek - Kek - Kek - Kek - which usually get louder and lighter in pitch. The male also makes soft chuckling noises when the female is working on the nest cavity,
Distribution area and habitat of the northern oriental hornbill
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The northern oriental hornbill ( A. a. Albirostris ), which is the nominate form of the species, occurs in India along the foothills of the Himalayas, in the south of Nepal, in the south of Bhutan, in the north of Bangladesh, Myanmar and in the west of the Chinese province of Yunnan and in the south of Xishuangbanna and Guangxi , in Vietnam, Laos and Cambodia. In Thailand the distribution area extends to Phattalung , Phuket and Tarutao . The nominate form also occurs in the northeast of the Malay Peninsula. In the distribution area, the nominate form is also often found on islands off the coast.
The nominate form inhabits forest edges and open deciduous and evergreen forests. In the north of Thailand, the species occurs up to an altitude of 670 meters. The nominate form is adaptable and is also found in coastal forests, in forests along rivers, in bamboo thickets, wooded gardens and along rice fields. Although the subspecies is basically a resident bird, there are migrations in the south of Nepal as a result of changing food supply.
Distribution area and habitat of the Sunda oriental hornbill
The Sunda oriental hornbill ( A. a. Convexus ) occurs in southern Thailand and on the Malay Peninsula. Singapore is also part of the historical distribution area of this subspecies, where it occurs mainly on the island of Ubin in the northeast of Singapore . The subspecies also lives on numerous islands in Indonesia. These include Sumatra and the Riau Islands , Nias , the Batu Islands , Java and the neighboring island of Legundi , Panaitan , western Bali, Borneo, the Tambelan Islands and Brunei.
The subspecies is most common in coastal regions and on coastal islands. It is possible that the hornbill in these regions is partly displacing the hornbill , with whose range it overlaps. On Sumatra, the subspecies predominantly inhabits forest edges and lightly forested regions in the lowlands, but occurs in forests along rivers up to 700 meters above sea level.
food
The hornbill mainly eats fruit, but also supplements it with insects and small vertebrates. As is typical for hornbills, it does not drink water, but rather covers its fluid requirements with its food. He looks for his food mainly in the treetops. However, especially near rivers, it regularly comes to the ground to look for food. In doing so, he moves forward hopping.
Like many hornbills, the fruits eaten include figs, which make up a large proportion of their diet. In addition, he also eats stone fruits and the fruits of corypha -Art Corypha utan , berries, the fruits of various climbing plants and papayas . The fruits of the oil palm , introduced in Asia, also play a role in the diet.
The hornbills catch insects in flight. A tame oriental hornbill has been observed to be able to catch flying swallows and bronze males . Oriental hornbills have also been observed successfully catching fish in shallow ponds. The other vertebrates that the hornbill eats include nestlings of various smaller bird species, some of which they also get from nesting holes, as well as smaller adult birds as well as bats, lizards and snakes. It also eats scorpions and snails, beetles, crickets, cockroaches, moths, butterflies, grasshoppers and termites.
Way of life
Oriental hornbills usually live in pairs or in small family groups of four to six individuals. Up to 50 individuals of this species can gather on very abundant fruit-bearing trees, which often look for food in this tree together with other fruit-eating species. After the breeding season, there are occasionally loose associations between 30 and 50 individuals. Larger accumulations also occur at nightly resting places. Concentrations of up to 130 individuals have been observed in Thailand. In principle, the number of individuals that spend the night in such a resting place varies and, unlike the hornbill , which belongs to the same genus, the resting places are always changed.
Such accumulations, as they come together in the resting places, are often noticeable from afar by their loud calls. Breeding hornbills, on the other hand, rarely call and usually behave very clandestinely.
Oriental hornbills often take sunbaths. They tilt one head to one side and open one or two wings slightly. The feathers on the head, neck and back are ruffled. They usually bathe in the rain-damp branches. It has also been described that wild hornbills take dust baths on the ground. However, this behavior has not yet been observed in oriental hornbills kept in human care.
Reproduction
Oriental hornbills are monogamous birds. Mated individuals can also be recognized outside of the breeding season, among other things, by the fact that they look after each other's plumage or offer each other parts of food. A participation of young birds in the rearing of the new brood, as is occasionally found for individual hornbills, is not observed in the oriental hornbill.
Oriental hornbills nest in natural tree hollows. in the distribution area of the nominate form, oriental hornbills compete with, among others, the furrow hornbill and the austen hornbird for suitable nesting holes. Only the female cleans the nest cavity, the male stays near the cavity during this time and makes gently chuckling sounds. However, the male brings earth that the female uses to close the nest cavity. The entire incubation period lasts between 79 and 89 days, of which 25 to 27 days fall on the incubation of the eggs and six to seven weeks on the nestling period. The clutch usually consists of three eggs, but up to four eggs have been observed in one clutch. The time at which the female leaves the nest cavity is variable. Leaving the nest cavity was observed both 20 days before the young birds fledged and leaving the nest cavity after the last young bird had fled out. The latter behavior is rare for hornbills.
The female walls herself up in the cave before laying eggs. It only leaves a small gap open. During the breeding season it goes through the moulting of the large plumage. The male feeds the females and later the offspring with choked up food. In captive birds, it has been found that a very high protein diet is a key success factor for successful young rearing. Up to ten mice per day were fed to a male who raised two to three young birds in addition to the female. The young birds are able to fly when they leave the cave. They are fed by the parent birds for up to three weeks.
attitude
Oriental hornbills are occasionally shown in zoological gardens. The Northern hornbill has already reached the age of 21 years in captivity, a Sunda hornbill was at least 29 years old.
literature
- W. Grummt , H. Strehlow (Ed.): Zoo animal keeping birds. Verlag Harri Deutsch, Frankfurt am Main 2009, ISBN 978-3-8171-1636-2 .
- Alan Kemp: The Hornbills - Bucerotiformes. Oxford University Press, Oxford 1995, ISBN 0-19-857729-X .
Web links
- Anthracoceros albirostris in the endangered Red List species the IUCN 2012. Posted by: BirdLife International, 2012. Accessed October 26, 2016th
- Calls of the oriental hornbird on Xeno-Canto
Single receipts
- ↑ Anthracoceros albirostris in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Retrieved on 3 October 2017th
- ↑ a b c Kemp: The Hornbills - Bucerotiformes. P. 166.
- ↑ a b c Kemp: The Hornbills - Bucerotiformes. P. 165.
- ↑ Calls of the Oriental Hornbird on Xeno-Canto , accessed on October 27, 2016
- ↑ a b c d e f Kemp: The Hornbills - Bucerotiformes. P. 167.
- ↑ a b c d e Kemp: The Hornbills - Bucerotiformes. P. 168.
- ↑ Kemp: The Hornbills - Bucerotiformes . P. 169.
- ↑ Kemp: The Hornbills - Bucerotiformes. P. 170.
- ↑ W. Grummt, H. Strehlow (Ed.): Zoo animal keeping birds. P. 546.