Long-tailed shrike
| Long-tailed shrike | ||||||||||||
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Long-tailed shrike |
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| Lanius cabanisi | ||||||||||||
| Hartert , 1906 |
The long-tailed shrike ( Lanius cabanisi ) is a songbird from the genus of the real shrike ( Lanius ) within the family of the shrike (Laniidae). Few details are known about the biology of this species.
The very large, conspicuously black and white drawn shrike occurs mainly in the dry savannahs of East Africa . He lives individually, in pairs, but more often in small social groups of up to 6 individuals. L. cabanisi is a resident bird . Outside of the breeding seasons, the groups roam small areas. Like most species of shrike, it is a hide hunter who feeds primarily on insects and small vertebrates such as lizards and mice .
The systematic position of the long-tailed shrike is unclear. Mostly he is with the living also in social associations Gray-backed fiscal into a super species Lanius excubitorius (= syn. L. excubitoroides ) For both species, the subgenus was Neolanius set up, but this assignment is no longer common. No subspecies are described.
There are also no detailed studies of the species population. At least regionally, L. cabanisi seems to be not uncommon. Its range is relatively small, but it does not appear that there are any serious current threats to its habitat. As a result, the IUCN classifies the population of the species as harmless (LC = least concern) .
Appearance
The long-tailed shrike is a large, slim-looking, but robustly built, black and white shrike with a remarkably long tail. Its body length is between 26 and 30 centimeters, of which the tail takes up about half. It can weigh up to 80 grams. L. cabanisi is slightly larger than the northern gray shrike with about the same body weight . The female is slightly smaller and lighter and has a rusty-brown, fluffy plumage region on the flanks with otherwise the same plumage.
The forehead, skull, crown and neck are deep black. The face mask is weakly recognizable due to an even stronger color saturation in good lighting conditions. The coat and upper back are dark gray, the lower back section becomes slightly lighter. The top of the wings is black-brown. The basal portions of the primaries , and some feathers of the outer and inner secondaries are white. This creates a mostly conspicuous, white wing field in the seated bird , while in flight a clear, sickle-shaped, white marking. The rump is matt white or light gray, as are the coverts on the top of the tail. The latter can have a light-colored end band , or be speckled or dripped white in the end area. The long, clearly stepped tail is black-brown; in the fresh plumage, fine white markings can be seen in its end area. The entire underside of the body is pure white; the undersides of the wings and tail are dark slate gray. The mighty hooked bill is black, as are the legs. The iris of the eyes is blackish brown.
Juveniles are very densely wavy yellow-brown on the upper side on a gray-brown background, the rump is cream-colored, the wings, which are almost black, are clearly bordered with light brown, as are most of the coverts on the wings and tail. The face mask is clearly visible. The dark brown tail has irregularly distributed, light colored points. The underside of the body is matt white and, especially on the chest, finely wavy and dark. The flanks are rusty brown. The beak is gray-brown.
Mauser
Very few details are known about the timing and type of moult . Apparently all feathers are changed during the moulting of the young birds in the adult plumage as well as during the annual moulting of the adults. The adult birds begin moulting after the breeding season, i.e. mostly in the dry season from July. How long the moult lasts and at what age juveniles switch to the first adult plumage is not known.
Vocalizations
The species is acoustically very noticeable. The groups gather regularly on the outskirts of their territories, where they shout and shout under constant tail stilts and tail circles. The calls uttered are different, but all have a rough, sometimes pressed, croaking-screeching sound characteristic. Keckernde sounds and Schnabel miners are also common to hear in these group meetings. As a largely universal warning and aggression call , a single or a row , jay- like Tschää , Tscherr or Kerrr can be heard. Other utterances consist of whistling tones and sound imitations of various kinds. Probably mainly in the sexual context there is a more melodious two-syllable kech-wa .
distribution and habitat
orange: Long-tailed Shrike
green: Makinnonwürger
yellow: São Tomé Strangler (arrow and small card left)
Lanius cabanisi is common in eastern Africa south of the Sahara, both north and south of the equator . It lives in suitable habitats in southern Somalia , especially near the coast , in central and southern Kenya as well as in northern, north-eastern and central Tanzania . A larger island is located east of Lake Victoria , in whose western part the Makinnon shrike and the long-tailed shrike occur sympatric . The ranges of the Somali strangler , the northern fiscal strangler and the Taita strangler also partially overlap with the range of L. cabanisi . No hybrids have been observed so far .
The long-tailed shrike particularly prefers dry habitats such as savannahs of various types. Thorn bush thickets on the edge of grass savannahs as well as dry savannahs with bushes and loose trees are often settled. The species is also found in very open wooded areas and in the fringes of cultivated land. In addition to a sufficient supply of food, the main habitat props are sitting areas . Regions with short or no vegetation are preferred. L. cabanisi is widespread as a breeding bird from the lowlands up to heights of 1600 meters. No information is available on population density and area size.
Food and subsistence
The food of the long-tailed shrike consists mainly of insects , among which beetles and grasshoppers occupy a dominant position, as well as of vertebrates such as small songbirds and their nestlings , lizards , geckos , young snakes and small rodents . Occasionally he eats fruits, for example those of the toothbrush tree, and uses leftover food.
Like the majority of stranglers, L. cabanisi is also a hide hunter . From a seat of different heights, he searches the ground for prey and hits them after a short glide flight. Occasionally he also reads prey from substrate surfaces (leaves, tree bark), or collects them from the ground. Air hunts were observed very rarely. It is very likely that the species will impale prey and store supplies. Often long-tailed shrike are observed in a mutualistic hunting relationship with the buffalo weaver , in which the shrike benefit from the insects that are frightened by the swarm of weavers, the weavers from the watchfulness and warning calls of the shrike.
General behavior and breeding biology
Like all stranglers, the long-tailed shrike is also diurnal. The species spends the relatively short equatorial day mainly with activities that are related to the procurement of food, the claiming of territory and - during the breeding season - with brood and brood care. The species lives alone, in seasonal pairs, but in most cases in small groups of 4–6 individuals. The composition of the group members and their social organization is not known, but it is assumed that it is mostly a couple of parents with the young and old boys. The group members are in constant acoustic and visual contact, whereby the long tail, which is constantly stilted, spread and turned, has a special optical function. Especially in the evenings, the group members gather in a bush at the territorial borders with loud calls. The long-tailed shrike is a resident bird. In some cases, individual individuals were found south of the known breeding areas, which indicates at least occasional migratory movements.
The courtship and pairing has not yet been described; Nothing is known about the average duration of the couple bond either. It has also not yet been possible to determine whether cooperative incubation with incubation aid takes place. At the nest - during incubation and shading, huddling and feeding - only one breeding pair has ever been observed.
The breeding seasons are not as dependent on the rainy seasons as with other species. In Somalia they are in May and June, in Kenya between January (December) and May and between August and October and in Tanzania between January and June. The nest is usually built in a dense bush or tree at heights between 2 and 3 meters. It is an open bowl made of blades of grass and twigs, often camouflaged with cobwebs at the top. The clutch consists of 3–4 eggs with different intensities of yellow, dark brown and pink spotted eggs on a cream-colored background. The brood begins with the first egg. The chicks hatch after 13-14 days and leave the nest after 16-18 days.
Systematics
The long-tailed shrike was first described in 1906 by Ernst Johann Otto Hartert . The type specimen comes from the area around Mombasa . The specific epithet honors the German ornithologist Jean Louis Cabanis , who died in the year of the first description.
The species is monotypical . It is usually understood as a superspecies together with the gray- coat shrike and was previously placed in a subgenus Neolanius , which is no longer valid today . This assignment is based on morphological, but above all on behavioral similarities. To what extent molecular biological investigations can confirm these assessments is still pending.
Inventory and inventory development
There are no detailed surveys available. The species, found in some protected areas such as Nairobi National Park , Tarangire National Park , and Mikumi National Park , appears to be not uncommon, but its range is not very extensive. The extent to which the increasing control of the bloodbeak weaver with chemical poisons also influences the population density of the long-tailed shrike has not yet been evaluated. According to the IUCN, the population is currently stable and the population of the species is not endangered.
literature
- Tony Harris, Kim Franklin: Shrikes & Bush-Shrikes. Including wood-shrikes, helmet-shrikes, flycather-shrikes, philentomas, batises and wattle-eyes. Christopher Helm, London 2000, ISBN 0-7136-3861-3 .
- Norbert Lefranc, Tim Worfolk: Shrikes. A Guide to the Shrikes of the World. Pica Press, 1997, ISBN 1-4081-3505-1 .
- Reuven Yosef, E. de Juana: Long-tailed Shrike ( Lanius cabanisi ). In: J. del Hoyo, A. Elliott, J. Sargatal, DA Christie, E. de Juana (Eds.): Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona 2013 ([retrieved from http://www.hbw.com/node/60486 ]), accessed July 7, 2016.
- Evgenij N. Panov: The True Shrikes (Laniidae) of the World - Ecology, Behavior and Evolution. Pensoft Publishers, Sofia 2011, ISBN 978-954-642-576-8 .
Individual evidence
- ↑ a b c d e f Reuven Yosef, E. de Juana: Long-tailed Shrike (Lanius cabanisi). In: J. del Hoyo, A. Elliott, J. Sargatal, DA Christie, E. de Juana (Eds.): Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona 2013 ([retrieved from http://www.hbw.com/node/60486 ]), accessed July 7, 2016.
- ↑ a b c d e f g h i T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 169.
- ↑ Lanius cabanisi in the IUCN Red List of Threatened Species 2014.3. Listed by: BirdLife International, 2012. Retrieved July 17, 2016.
- ↑ Sound recordings at xeno-canto
- ^ Eugene M. McCarthy: Handbook of Avian Hybrids of the World . Oxford University Press; Edition: 1 (February 16, 2006). ISBN 978-0-19-518323-8
- ^ André Brosset: Un cas d'association à bénéfice mutuel, celui de la Pie Grièche Lanius cabanisi avec les bulabornis Bulalornis niger. In: Revue d'Écologie 1, pp. 103-106, 1989
- ^ Andrew N. William and Robert A. Cheke: A review of the impacts of control operations against the red-billed quelea (Quelea quelea) on non-target organisms. In: Environmental Conservation 31: 2 (2004). Pp. 130-137
