Rust-coated shrike
| Rust-coated shrike | ||||||||||||
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Rust-mantled shrike, adult male |
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| Scientific name | ||||||||||||
| Lanius souzae | ||||||||||||
| Bocage , 1878 |
The rust- mantled shrike ( Lanius souzae ) is a songbird from the genus of the real shrike ( Lanius ) within the family of the shrike (Laniidae).
The small, only about lerch large brown-gray shrikes somewhat reminiscent of a pale-colored red-backed shrike , from that but easily distinguished by the distinct white shoulder stripes. It comes in a relatively large area, especially in the southern central Africa south of the equator, especially in Miombo - forest savannas before. It lives singly or in pairs, but is also often seen in small groups of four to five individuals.
Like the majority of the representatives of this genus, the rust-mantled shrike is also a hide hunter , who feeds primarily on invertebrates and only occasionally on small vertebrates . The species is considered a resident bird , but small-scale migrations in the southern winter have also been identified.
The shy, inconspicuous species has not been adequately researched. Hardly any information is available on its distribution density, but it is currently (2016) not listed in any hazard level. The red-eared shrike, which is common north of the equator, is considered a sister species , but more recent studies indicate a very close relationship to the southern fiscal shrike . In addition to the nominate form, there are two other, slightly differentiated subspecies .
Appearance
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The rust-mantled shrike is a little conspicuous, also in its vocalizations rather quiet, slim type of shrike. In size (17-18 centimeters) and weight (max. 30 grams) it resembles the red-backed shrimp, to which it is also similar in habit and plumage, but has clear white shoulder markings. In addition, forest savannahs are their habitat, while the red- backed shrike mainly lives in thorn bush savannahs in winter . The red-eared shrike is also very similar, but the ranges of the two species are widely separated. The sexual dimorphism is limited to a moderate difference in color: females are somewhat paler in color and have reddish-brown hues on the flanks.
The crown, neck and coat are pale gray. The black face mask is noticeable; it begins at the base of the beak and runs over the eyes to the ear covers . Towards the vertex it is bordered by a light feather region that is not always clearly recognizable. The shoulders are white, the back very finely banded in black on a dull brown background. The rump is rather gray-brown and hardly banded. The wings are dull brown, the cover feathers rather reddish brown and finely banded in black. The wings of the hand do not have a white basal region, which is why there is no white wing field in the seated bird . The underside is cream-colored to whitish, sometimes with very fine dark markings. The long, narrow, only slightly rounded tail has reddish brown and black banding on a dull brown background. Except for the middle pair, all tail feathers are irregularly dripped in white, the outer flags of the edge feathers are partly white. The bill is black except for the significantly lighter base of the lower mandible, the legs are dark gray, the iris is dark brown.
Fledglings are reddish brown on top and dirty white on the underside. The shoulder region is whitish. They are noticeably darkly banded and flocked all over the body. The face mask is brownish and only vaguely recognizable.
Mauser
There is hardly any information. Probably an annual complete moult during the post-breeding season. The wings may be molted separately.
Vocalizations
The vocalizations have hardly been researched and only a few are documented. The species does not seem to be acoustically very noticeable. The most common sound is a muffled, slightly vibrating tsiiie , which is likely of territorial character. Even inharmonious sounding tsii-jert call series seem to be in the same context. In the pre-breeding season, the male can be heard with a soft, chattering song interspersed with harsh elements. The alarm call is described as a screeching, scratchy sound.
distribution and habitat
The distribution area of the rust-coated shrike is entirely in Africa south of the equator.
It stretches from central and north-east Angola , the south of the Democratic Republic of the Congo , eastwards through Zambia and Malawi to the west of Tanzania and the north-west of Mozambique . While the species is relatively widespread in the west, the occurrences loosen up towards the east. Largely isolated islands are in the north-west in the Republic of the Congo and in Gabon , in the north-east, west and south of Lake Victoria in north-west Tanzania and in Rwanda, and in the south-west and south in southern Angola and in northern Botswana . Observations from southern Burundi and northern Namibia are not confirmed .
The rust-mantled shrike is largely, but not exclusively, tied to Miombo tree savannahs, in which trees from the Brachystegia genus are the leading plants. He prefers areas with short or no grass cover and loosened trees. The species also appears in savannah types where other deciduous trees such as Uapaca sp., Burkea sp. or Baikiaea sp. prevalence. In Rwanda it occurs exclusively in pericopsis populations. The rust - mantled shrike does not breed in pure thorn bush savannah , but colonizes the edge areas of the Acacia - Compretum savannah. Broods are only found sporadically in large gardens or on the outskirts of settlements.
Little is known about the vertical distribution of the rust-coated shrike. The observations made so far show it as a kind of medium altitude, between 700 and 1800 meters.
The species is considered a resident bird. However, since it disappears completely from some breeding areas in the southern winter, local, small-scale migratory movements are suspected. Small-scale migration during the dry season is also likely.
There is no information on the size of the area or space requirements.
Biological details
Food and subsistence
Detailed information is not available. Cicadas and large spiders have been identified, but the range of prey is certainly much more extensive and will include a wide variety of insect species and occasionally small vertebrates. An attack on a sparrow-sized violet-coated nectar bird has been documented.
Like most species of the Lanius genus , the rust-mantled shrike is primarily a hide hunter who searches the ground for prey from a seat guard in an inclined or almost horizontal position . With stranglers of this size, the greatest hunting success is within a radius of about 10 meters. If it spies a suitable prey, it slides from the hide and hits it on the ground. Smaller prey is eaten on the spot, larger prey carried back to the hide and cut up there. It is not known whether the rust-coated shrike impaled prey .
Behavior and Breeding Biology
Like all stranglers, the rust-coated shrike is also diurnal. He is mostly in the lower canopy of deciduous trees; if disturbed, he flees to higher regions. The species is often found in small groups of 3 - 5 individuals, so that breeding aid is not unlikely. There is no information about the extent and type of territoriality or the number of annual broods.
The species breeds between September and December in the northern part of its range and between September and November further south. She builds elaborately constructed small but deep bowl nests, which often lie freely on a branch. They are very reminiscent of the nests of birds of the genus of the spectacled shrike . On the outside, the nest is camouflaged with materials from the environment and with cobwebs. The construction of the nest takes up to three weeks. The clutch consists of 3 - 4 pale green or dirty yellow, brown, purple and gray spotted eggs. Probably only the female breeds. Further information is not available.
Systematics
The species was first described in 1878 by the Portuguese zoologist José Vicente Barbosa du Bocage . The type specimen comes from Caconda in central Angola. He chose the specific epithet souzae in honor of José Augusto de Sousa , a Portuguese ornithologist.
The majority of the rust-mantled shrike is closely related to Lanius gubernator and is regarded as its sister species. Fuchs et al. found in their extensive investigation, however, very close relationships to the group of southern fiscal stranglers. However, the aforementioned work focuses on the fiscal strangler and a number of other species have not been considered.
Three subspecies are described. The birds become slightly none and brighter to the south.
- Lanius s. souzae Bocage , 1878 : Northwest distribution area.
- Lanius s. burigi Chapin , 1950 : Rwanda, Burundi and western Tanzania. Wings and back gray-brown. No banding on the lower back and the upper tail covers. Rust-red flank coloring of the females more intense than that of L. s. souzae .
- Lanius s. tacitus Clancey , 1970 : Southeast Angola , Katanga , northern Botswana, western Malawi and northern Mozambique. Coat olive brown, wings as in the nominate form, but somewhat paler; rust-brown flank coloration of the females washed out and smaller. Overall smaller than L. s. souzae and L. s. burigi .
Persistence and Threat
The population of the species is largely unknown. The conversion of miombo savannahs into areas suitable for tobacco cultivation or the excessive removal of wood, which is needed to dry the tobacco but also as firewood, endangers the habitat of the species. The rust-coated shrike is nowhere considered a common species, but is because of its hidden nature Lifestyle is also often overlooked. The IUCN classifies the population trend as decreasing, but does not list the species in any endangerment category.
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 & International Shrike Working Group (2016): Souza's Shrike (Lanius souzae) . In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, DA & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (downloaded from http://www.hbw.com/node/60475 on September 12, 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 g h i j T. Harris, K. Franklin: Shrikes & Bush-Shrikes… 2000, p. 196.
- ↑ a b Lanius souzae in the IUCN Red List of Threatened Species 2014.3. Posted by: BirdLife International, 2012. Retrieved September 12, 2016.
- ^ A b c Reuven Yosef & International Shrike Working Group (2016): Souza's Shrike (Lanius souzae) . In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, DA & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (downloaded from http://www.hbw.com/node/60475 on September 12, 2016).
- ↑ Jérôme Fuchs, Timothy M. Crowe and Rauri CK Bowie: Phylogeography of the fiscal shrike (Lanius collaris): a novel pattern of genetic structure across the arid zones and savannas of Africa. In: Journal of Biogeography (J. Biogeogr.) (2011). P. 8
- ^ A b T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 195.
- ↑ Voice example from xeno-canto
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, pp. 113–115.
- ↑ JME Took: The Nest of Souza's Shrike
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 91.
- ^ James A. Jobling: Scientific Bird Names. Christopher Helm London Reprint 2011. ISBN 978-1-4081-2501-4
- ↑ Jérôme Fuchs, Timothy M. Crowe and Rauri CK Bowie: Phylogeography of the fiscal shrike (Lanius collaris): a novel pattern of genetic structure across the arid zones and savannas of Africa. In: Journal of Biogeography (J. Biogeogr.) (2011). P. 8
- ↑ Norbert Lefranc, Tim Worfolk: Shrikes. A Guide to the Shrikes of the World. Pica Press, 1997, ISBN 1-4081-3505-1 . P. 108
- ↑ Mwita M. Mangora: Ecological impact of tobacco farming in miombo woodlands of Urambo District, Tanzania
