Collared Bearded Bird
| Collared Bearded Bird | ||||||||||
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Collared bearded bird ( Lybius torquatus ) |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Lybius torquatus | ||||||||||
| ( Dumont , 1816) |
The Collared Bearded Bird ( Lybius torquatus ), also known as the black-necked bearded bird , is a species of the African bearded family . Within this family he is assigned to the tooth beard birds . The species occurs in Africa south of the equator and has a very large distribution area. Several subspecies are distinguished. The IUCN classifies the collared bearded bird as 
(= least concern - not endangered).
Appearance
The males of the nominate form reach a wing length of 8.8 to 9.6 centimeters. The tail reaches a length of 5.3 to 6.1 centimeters. The beak length is 2.15 to 2.48 centimeters. Females have similar body measurements. As is characteristic of tooth-bearded birds, there is no noticeable sexual dimorphism .
In males and females, the forehead, the skull, the face, the anterior ear covers, the chin and throat, and the front chest are usually red. In a few individuals the color is also orange-red or pink-red. A shiny black band runs along the back of the ear covers, the sides of the neck, the front back and as a narrower band across the center of the chest. On the middle of the back, the Collared Bearded Bird is brownish with small black and pale yellow spots, the rump and the upper tail-coverts are completely yellow in some individuals. The control springs are brown on the top and gray-brown on the bottom. The underside of the body below the black chest band is yellowish and in some individuals has fine brown-black speckles. The sides of the body and flanks are pale yellowish-white, the under tail-coverts are yellow-white and sometimes have brown longitudinal stripes. The wings are brown with narrow yellow edges.
The beak is very strong and large in relation to the body size. It is black. The featherless skin around the eyes is gray-black, the eyes vary from red to violet-red to maroon or brown. The feet and legs are gray to black.
Young birds are similar to adults , but the red areas on the front body are initially limited to small spots on the chin, throat and chest. They are generally paler yellowish than adults and the black band appears brownier on them. The eyes are gray.
The collared bearded bird is a very conspicuous and shouting bearded bird , which, due to the combination of red head, black collar and yellowish underside, can hardly be confused with any other bird species. The distantly similar red-faced bearded bird is black on the underside of the body, the brown-breasted bearded bird is white from the lower breast to the belly. It also lacks a darker band that runs across the center of the chest.
distribution
The range of the Collared Bearded Bird is estimated to be 4.7 million square kilometers. It stretches from northern Angola through the south and east of the Democratic Republic of the Congo , southwest Uganda , east Rwanda , Tanzania and the coastal region of Kenya to northern Namibia , north and east Botswana , the South African province of Free State and east South African Cape Province , Swaziland and southern Mozambique .
Collared bearded birds generally occur between sea level and altitudes of 1,600 meters. In Angola they are also observed at 1,820 meters.
habitat
The habitat of the Collared Bearded Bird are open forests, tree-lined grassland, forest edges, gardens and tree-lined cultivated land. They are absent in dense forest, very dry forest areas, in bushland and in the desert. In the regions where the Collared Bearded Bird occurs together with the Red-Faced Bearded Bird, the Collared Bearded Bird can be seen in more dense stands of trees and in forests along the banks of water.
Way of life
Collared bearded birds live either in pairs or in small flocks of up to six individuals. These flocks are almost certainly the parent birds with their fully grown, but not yet mated offspring. These offspring take on a helper role in defending the nest box.
Collared bearded birds show a series of interactions with the red-faced bearded bird, the now rare fig bearded bird , the brown-breasted bearded bird, the mirror , olive and straw-headed bearded birds belonging to the genus Stactolaema . Interactions include greetings and even cross-species duets. The collared bearded bird has also been observed widening the entrance of the nest cavities of the much smaller yellow -fronted dwarf bearded or slipping into the nest cavity of the diademed bearded bird . Both actions towards these smaller bird species are probably due to competitive behavior. The nesting cavities were unsuitable for the Collared Bearded Bird in both cases because they were hacked into relatively thin branches that did not allow the Collared Bearded Bird to expand the nesting cavities to a size suitable for it.
The food spectrum of the collared bearded birds consists mainly of fruits. Among other things, guavas, figs and berries are eaten. They also eat insects. They are territorial birds, the size of the territory fluctuating depending on the local conditions. In Kenya the area was about 21 hectares, in Zambia 50 and in South Africa up to 125 hectares. They are cave breeders who make their own cave in a dead tree or branch. Usually a new burrow is made in each breeding season, but it happens occasionally that they use old nesting holes a second time. They have also been observed in the abandoned nesting holes of woodpeckers. Only the mated pair of a troop is involved in building the nest box. The nest cavity is usually two to four meters above the ground.
The small honey indicator is one of the breeding parasites of the collared bearded bird . This species of bird responds to the duet chants of the collared bearded birds. It has already been observed that a small honey indicator attacked individual collared bearded birds within a flock. Possibly it was the male who distracted the troop so that his female could lay her egg in the nesting cavity of the collared bearded birds. The bloody remains of females of the small honey indicator have also been found in the nesting cavities of collared bearded birds, which indicates that although this species parasitize collared bearded birds to a large extent, they have a defensive behavior against it.
The clutch consists of one to five eggs. The breeding season is not known; after hatching, one member of the flock always stays near the nest box for a period of five to six days. The parent birds and the helpers bring food. The nestlings gradually open their eyes between the ages of 11 and 19, and when they are around 28 days old they appear at the cave entrance when food is brought in. They fly out at around 33 to 35 days of life. The family association stays together for at least five months, at least some of the surviving juveniles remain in the troop.
supporting documents
literature
- Lester L. Short, Jennifer FM Horne: Toucans, Barbets and Honeyguides - Ramphastidae, Capitonidae and Indicatoridae. Oxford University Press, Oxford 2001, ISBN 0-19-854666-1 .
Web links
Individual evidence
- ↑ a b BirdLife factsheet on the Collared Bearded Bird , accessed on February 26, 2011
- ↑ Short, Horne: Toucans, Barbets and Honey guides. 2001, p. 206.
- ↑ Short, Horne: Toucans, Barbets and Honey guides. 2001, p. 205.
- ^ A b Short, Horne: Toucans, Barbets and Honeyguides. 2001, p. 208.
- ↑ Short, Horne: Toucans, Barbets and Honey guides. 2001, p. 210.
Web links
- Lybius torquatus inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved January 30, 2014.