White-headed hornbill
| White-headed hornbill | ||||||||||
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White-headed hornbill |
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| Systematics | ||||||||||
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| Scientific name of the genus | ||||||||||
| Tropicranus | ||||||||||
| WL Sclater , 1922 | ||||||||||
| Scientific name of the species | ||||||||||
| Tropicranus albocristatus | ||||||||||
| ( Cassin , 1848) |
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The white crested hornbill ( Tropicranus albocristatus , Syn. : Horizocerus albocristatus ), also Perückentoko or bald hornbill called, is an African bird art that the hornbills belongs (Bucerotidae). Like all hornbill species, the white-headed hornbill is a cave breeder. The female walls herself up in the nest cavity and is fed by the male during the breeding season. There are three subspecies.
The population of the white-headed hornbill was classified in the IUCN Red List of Threatened Species in 2016 as “ Least Concern (LC) ” = “not endangered”.
features
Features of the nominate form
The white-headed hornbill is one of the large hornbills and can reach a body length of up to 70 centimeters. The beak is 9.1 to 10.3 inches long in the males. Females have a significantly shorter beak with a length between 6.7 and 7.4 centimeters. The difference in weight is not as pronounced: females weigh an average of 282 grams, while males weigh between 279 and 315 grams. The sexual dimorphism is not very pronounced. Females correspond to males in body plumage, but stay smaller and have a shorter beak ridge.
In the white-headed hornbills, the head including the vertex and the neck feathers is white, the individual feathers have black feather shafts and black tips. The rest of the plumage is black with a metallic sheen. Only the tail feathers have white feather tips.
The beak is predominantly dark gray, with a cream-colored section at the base of the upper beak. The ridge of the beak is dark and ends abruptly just before the tip of the beak. The orbital ring is blue, the feathered throat patch is flesh-colored. The eyes are brown to cream in color, the legs and feet are dark blue-gray.
Young birds resemble adult birds, their irises are still pale blue, the basic color is greenish, the beak's beak is initially missing.
Characteristics of the subspecies
In addition to the nominate form Tropicranus albocristatus albocristatus, two further subspecies are distinguished:
- Tropicranus albocristatus cassini ( Finsch , 1903) - Occurrence from eastern Nigeria to Uganda and southern Angola . The subspecies is slightly larger than the nominate form, the head sides are black and only the head of feathers is white.
- Tropicranus albocristatus macrourus ( Bonaparte , 1850) - Occurring from the Ivory Coast to Ghana . In this subspecies, the neck is also spotted white and gray.
voice
The white-headed hornbill is not very happy to call, but the calls have a noticeable timbre. A call sequence of croaking sounds is followed by a rough, howling uoo-uoo - uoo-aah-aah . The contact sounds are a short squark .
Distribution area and habitat
The distribution area of the white-headed hornbill is western sub-Saharan Africa . The species occurs in Guinea, Sierra Leone, Liberia, the Ivory Coast, Ghana, Togo, Benin, Zaire, Congo, Uganda, in the Central African Republic and in northern Angola.
The habitat are predominantly dense moist and evergreen primary forests. However, it also occurs in secondary forest bordering primary forest, forests along rivers and even sparsely populated forest areas. It is often found near groups of monkeys. The altitude distribution extends up to 900 meters in altitude on Mount Nimba and up to 1500 meters in altitude in the Kivu area .
Way of life
The white-headed hornbill occurs mainly in pairs, which are accompanied by one to three young birds. There are territorial birds whose area is usually that of a group of monkeys (z. B. by Lowe-tailed monkeys equivalent). There is a loose protoco-cooperation between the two species . The monkeys benefit from the alarm calls of the white-headed hornbill. He follows them in the food trains and eats the small animals (mostly insects) that they scare off. He shows a similar behavior towards other bird flocks, but also wandering ants .
It mainly catches its food in flight, mostly flying up from the lower branches of the tops of high jungle trees. Occasionally he comes to the ground to look for food. According to observations, this behavior accounts for about 11 percent of its foraging. White-headed hornbills often sit motionless on branches while searching for food and search their surroundings for suitable prey with slow head movements.
The diet consists mainly of large insects, but also small vertebrates such as birds, mice, lizards, snakes and frogs. He only eats fruit occasionally, but among other things he eats the fruits of oil palms and comes to the ground to pick up the fallen fruits of Dacryodes .
Reproduction
Little is known about the reproductive behavior of the white-headed hornbill. The previously known nesting holes were in trees. The female seals the entrance to the brood cavity with her feces except for a narrow gap. It goes through a molt of the large plumage during this breeding season. The male carries individual prey in its beak to the nest cavity and gives it to the female there. Usually one young bird per brood grows, but the rearing of two young birds has also been observed.
Trivia
The name of the subspecies Tropicranus albocristatus cassini honors with cassini the American Quaker, businessman and ornithologist John Cassin (1813–1869), who served for more than a quarter of a century as the unpaid curator of ornithology of the Academy of Natural Sciences of Philadelphia. He is still considered to be one of the most important personalities among the American ornithologists and described more than 198 species of birds, including many that he himself brought back from his expeditions. He accompanied, among others, Admiral Matthew Calbraith Perry as an officially appointed ornithologist on his historic trip to Japan. In 1853 he was elected honorary member of the German Ornithological Society for his achievements .
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
- Horizocerus albocristatus in the endangered Red List species the IUCN 2014 Posted by: BirdLife International, 2014. Accessed October 23, 2016th
- Voice of the white-headed hornbill on Xeno-Canto
Single receipts
- ↑ Horizocerus albocristatus in the endangered Red List species the IUCN 2016 Posted by: BirdLife International, 2016. Retrieved on 3 October 2017th
- ↑ Kemp: The Hornbills - Bucerotiformes . P. 150.
- ^ Voice of the white-headed hornbill on Xeno-Canto , accessed on October 23, 2016.
- ↑ Kemp: The Hornbills - Bucerotiformes. P. 151.
- ↑ Kemp: The Hornbills - Bucerotiformes. P. 152.
- ↑ Kemp: The Hornbills - Bucerotiformes . P. 153.
- ↑ Bo Beolens, Michael Watkins: Whose Bird? Men and Women Commemorated in the Common Names of Birds . Christopher Helm, London 2003, ISBN 0-7136-6647-1 , pp. 205 .
- ^ August Carl Eduard Baldamus : Excerpt from the minutes of the seventh ornithologists' meeting in Halberstadt . In: Naumannia . tape 3 , 1853, p. 113–126 ( online [accessed July 28, 2011]).