Black cuckoo
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Black cuckoo ( Cuculus clamosus )
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| Latham , 1801 |
The black cuckoo ( Cuculus clamosus ) belongs to the order of the cuckoo birds (Cuculiformes) and to the family of the cuckoos (Cuculidae). Like numerous species of cuckoo birds, the black cuckoo is a brood parasite . The black cuckoo differs significantly from other species of the genus Cuculus with its dark body plumage. Erhitzøe thinks it is possible that this plumage is a form of mimicry that makes it easier for the black cuckoo to lay eggs in the nests of its host birds.
The black cuckoo occurs in the Afrotropic ecozone . Like many species of cuckoos, it is a compulsory brood parasite. Two subspecies for the black cuckoo are described.
features
The black cuckoo reaches a body length of 31 centimeters. It is a long-tailed cuckoo with an average tail length of 14.5 centimeters. The cuckoo's beak has an average length of 2.3 centimeters. Males weigh between 78 and 94 grams, the females weigh between 75 and 94 grams.
Features of the nominate form
The male is black on the upper side of the body with a greenish or bluish tinge. The wings are dull and dark brown in color. The inner vane of the flight feathers is white sparred. In some individuals there is also a whitish sparrow coat on the outer flags of the wings of the hand.
On the underside of the body, the black cuckoo is matt black. The throat, the sides of the neck and the chest are a little shinier and a little darker. In many individuals there is also a dull white or brownish sparrow coat, in some individuals the sparrow coat is red-brown. The under tail-coverts are either brown or have a whitish sparrowth. The control feathers have narrow white feather tips and in many individuals are partially striped across white.
The females are similar to the males, but are more pronounced on the belly. Young birds are predominantly black, they still lack the white tips of the tail feathers. The swing feathers are brown with whitish spots and dots on the inner vents.
The nestlings are naked when they hatch and have a brown-pink skin that quickly turns black-violet.
Differences between the subspecies C. c. gabonensis
The males of the subspecies C. c. gabonensis differ from the nominate form in the reddish brown to maroon color of the chin, throat, sides of the neck and chest. In some individuals, the chest is not pitted. The belly is pale brownish with a dense dark brown sparrow. The under-tail-coverts, on the other hand, have no sparrows and are strong red-brown. The wings are slightly more crenated than in the nominate form.
The females are more dull in color than those of the nominate form. The underside of the body is very heavily clogged. The control springs have pronounced white tips.
Distribution area of the two subspecies
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There are two subspecies of the black cuckoo:
- C. c. clamosus is the nominate form described by Latham in 1801.
- C. c. gabonensis is a nominate form described by Frédéric de Lafresnaye in 1853.
The nominate form occurs in the highlands of Ethiopia and Eritrea, in the west and inland of Kenya, Tanzania, in the south of the Democratic Republic of the Congo and from south Angola to the north and interior of Namibia, in the north of Botswana and in the east of the Republic of South Africa . They are migratory birds that migrate to western Equatorial Africa at certain times of the year . In Angola, for example, he can be found from August to March. In the north and interior of Namibia, for example, it is at home from November to April. Its arrival depends on the beginning of the rainy season.
The subspecies C. c. gabonensis is probably a resident bird. It occurs in Liberia, the Ivory Coast, Togo, Benin, Ghana, Nigeria, Gabon and in the north of the Democratic Republic of the Congo to the south of Sudan, in the south-west of Ethiopia, Uganda and from south-west Kenya to 9 ° S in Angola.
habitat
The black cuckoo occurs in forests of the lowlands, in gallery forests and the miombo as well as on tree-lined savannahs, in thickets, in acacia-lined Veld , forests along rivers and in the Republic of South Africa also in gardens. In Malawi it occurs in less abundant habitats than the hermit cuckoo .
In the Democratic Republic of the Congo and Malawi it is usually below 1525 meters in altitude, in Rwanda and in East Africa it is up to 2000 meters in altitude.
food
The black cuckoo mainly eats very hairy caterpillars, as is the case with many other cuckoo species. By contrast, heavily hairy caterpillars are mostly avoided by other bird species. It also eats flying termites that it catches in the air, ants, beetles and beetle larvae. It also eats eggs and nestlings - presumably these are the eggs and nestlings of its host birds.
Brood Parasitism
The black cuckoo is an obligatory brood parasite that does not raise its young birds itself. The host birds that it uses vary depending on its respective habitat. In the savannah he mainly uses species from the bush shrike family such as the red-bellied shrike, but also species such as the graubülbül .
The breeding season also varies with the area of distribution. The females remove one of the eggs from their host birds while they are laying eggs. A female can lay up to 22 eggs over a 10 week period. These are elliptical in shape, have a glossy white or greenish shell and are spotted with different reddish brown and purple. In the south of Africa, the cuckoo's egg sometimes exactly resembles the eggs of the host bird.
The nestlings of the black cuckoo hatch from the eggs after a breeding period of 13 to 14 days and are thus ready to hatch about three days earlier than the nestlings of the host birds. The still blind nestling throws eggs and the other nestlings of the host bird from the nest 16 to 30 hours after hatching. On the eighth day of life, the nestling's eyes open. It leaves the nest on the 20th or 21st day of life, but is still fed by the host bird parents for 19 to 26 days.
Trivia
The black cuckoo's brood parasitism has been known since the beginning of the 19th century: In 1806, the French ornithologist François Levaillant noted that, in addition to the Indian koel , the cuckoo and the Jacobin cuckoo, other species of cuckoo, namely the African cuckoo , the black cuckoo and the golden cuckoo , are hatching parasites .
literature
- NB Davies: Cuckoos, Cowbirds and Other Cheats . T & AD Poyser, London 2000, ISBN 0-85661-135-2 .
- Johannes Erhitzøe, Clive F. Mann, Frederik P. Brammer, Richard A. Fuller: Cuckoos of the World . Christopher Helm, London 2012, ISBN 978-0-7136-6034-0 .
