Hornbill
| Hornbill | ||||||||||||
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Hornbill |
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| Scientific name | ||||||||||||
| Bycanistes fistulator | ||||||||||||
| ( Cassin , 1850) |
The hornbill ( Bycanistes fistulator , Syn. : Ceratogymna fistulator ) is a bird art from the family of hornbills . Its distribution area is in sub-Saharan Africa . Three subspecies are distinguished in the large distribution area.
Like all hornbills, the screech hornbill is a cave breeder. The female walled up the brood cavity except for a narrow gap. During this time, the male first supplies them and later also the young birds with food.
The IUCN specifies the population of the screechhorn bird as not endangered ( least concern ).
features
The screech hornbill reaches a body length of 45 centimeters and is the smallest among the African throat pouch hornbills. The tail feathers account for an average of 20 centimeters in males and 18.4 centimeters in females. The males have a beak between 10 and 12.2 centimeters. The beak of the females remains slightly smaller and is 8.2 to 8.7 centimeters long. The gender dimorphism is only slightly pronounced.
Appearance of the males
In the male, the head, neck, front chest and back are glossy black. The upper tail and under tail coverts are white, the tail is black. The individual control springs have white tips except for the middle control spring pair. The underside of the body is white. The wings are black with white tips on the middle arm wings. The beak is gray-brown with a cream-colored beak base and a cream-colored beak tip. The beak attachment is a small ridge at the base of the beak. The featherless skin around the eye is dark blue. The eyes are red-brown, the legs and feet are black-brown.
Appearance of females and fledglings
The females resemble the males in their plumage, but they remain smaller. The beak is a little lighter. The small ridge of the beak is less noticeable than in the male. The featherless skin around the eyes is greenish blue, the eyes are brown.
Fledglings have plumage that is similar to that of adult birds. The beak is smaller than that of the adult birds and darker. Their beak ridge is not yet developed. At the base of the beak, feathers still have brown edges. The featherless skin around the eyes is pale greenish, the eyes are gray.
Appearance of the subspecies
The two subspecies differ from the nominate form described above in the following characteristics:
- Bycanistes fistulator sharpii ( Elliot , 1873) the inner hand wings and the middle arm wings are almost white. The beak ridge is slightly higher than in the nominate form and ends in the male at the tip. The featherless skin around the eyes is black.
- Bycanistes fistulator duboise ( Sclater , 1884) also has inner hand wings and middle arm wings that are almost white. In addition, however, the outer hand wings have broad white tips. The male's high beak ridge ends at the tip of the beak. The ridge of the beak and beak are cream-colored with a brown spot in the middle. The featherless skin around the eyes is black in the male and gray-green in the female.
Distribution area and habitat
The hornbill occurs in northwestern sub-Saharan Africa.
- The nominate form B. f. fistulator occurs in Senegal, Gambia, Guinea-Bissau, north and south of Guinea, Sierra Leone, Liberia, the Ivory Coast, and Ghana.
- the subspecies B. f. sharpii is found in Nigeria, Cameroon, Chad, Gabon, Congo, western Zaire, and Angola.
- the subspecies B. f. duboisi occurs in parts of Zaire, the Central African Republic, southern Sudan and western Uganda.
The screechhorn bird's habitat are lowland rainforests. It occurs in secondary forest, on oil palm plantations, small forest areas in savannah areas and mangrove swamps. When certain tree species bear abundant fruit, it can also be found deep inside dense primary forests.
Way of life
The hornbill prefers to stay in the crown area of the forests and prefers trees that tower over other trees due to their high growth. In their search for food, they end up in the crowns of these trees and, through their calls, draw the attention of other conspecifics to any fruit-bearing trees found. The hornbill usually lives in pairs or in small family groups. Occasionally, groups of 12 to 20 individuals also gather. During the rainy season, groups of 40 or 50 hornbills are very rarely formed. Couples or family groups generally stay together in these groups and occasionally change the group with which they roam an area during the course of the day. During the nocturnal rest, they are regularly gathered in large numbers. Here, too, they prefer very tall trees.
Food and foraging
Fruit-bearing trees are visited for several days in a row. Usually they only stay in a tree for about 30 minutes and then pick up about two to three fruits per minute. Like most hornbills, the hornbill is omnivorous, but its nutritional needs are largely covered by fruits. As with many hornbills, figs appear to play a particularly large role in its diet. The fruits and seeds of 30 different types of plants were found in his diet, including those of dragon trees , cissus , mistletoe and cassias . He also eats corn, the fruits of the oil palm, blossoms, saplings and young leaves. It also eats insects such as beetles, praying mantises and wasps.
Reproduction
The hornbill is one of the hornbill species whose reproductive biology has not yet been conclusively investigated. In Gabon it breeds in the short dry season from September to December. In Zaire, breeding birds have been observed from January to February and in July. The clutch consists of one to three eggs. However, pairs are usually only observed in the company of a young bird.
Hornbills are cave breeders. They use natural tree hollows for their breeding business, the cave is about 8 to 15 meters above the ground. As is typical for hornbills, the entrance is sealed except for a narrow gap. Feather finds in the root area of brood trees indicate that at least occasionally the female in the brood cavity walled up the large plumage at the same time.
The black- mantled hawk ( Accipiter melanoleucus ) has been shown to be a predator of the screechhorn bird. Hornbills kept in captivity reached an age of 8.7 years.
literature
- Mark Cocker, David Tipling: Birds and People. Jonathan Cape, London 2013, ISBN 978-0-224-08174-0 .
- 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
- Bycanistes fistulator inthe IUCN Red List of Endangered Species 2016.10. Posted by: BirdLife International, 2016. Retrieved December 10, 2016.
Single receipts
- ↑ a b c d e f g Kemp: The Hornbills - Bucerotiformes. P. 244.
- ↑ Bycanistes fistulator in the Red List of Threatened Species of the IUCN 2016.10. Posted by: BirdLife International, 2016. Retrieved December 10, 2016.
- ↑ Kemp: The Hornbills - Bucerotiformes. P. 243.
- ↑ a b Kemp: The Hornbills - Bucerotiformes. P. 242.