Northern fiscal strangler

Northern fiscal strangler
Northern fiscal strangler (male)
Systematics
Order : Passerines (Passeriformes) Subordination : Songbirds (passeri) Superfamily : Corvoidea Family : Shrike (Laniidae) Genre : Real strangler ( Lanius ) Type : Northern fiscal strangler
Scientific name
Lanius humeralis
Stanley , 1814

The Northern Fiscal Shrike ( Lanius humeralis ) is a songbird from the genus of the real shrike ( Lanius ) within the family of the shrike (Laniidae). The species was separated from Lanius collaris (fiscal strangler) in 2011 . Despite the very great similarity to the southern fiscal strangler, there are very clear genetic differences between the two species. The black-and-white drawn bird with the striking white V-markings on the back is up to 23 centimeters in length, a little smaller than the northern gray shrike but much larger than a red backed shrike .

The Northern fiscal shrike is in Africa south of the Sahara both north and south of the equator widespread. The species inhabits diverse, moderately humid to semi-arid habitats , but requires bushes, trees, termite mounds or fences or electricity pylons as perches and the lowest possible ground vegetation. It also penetrates settlements and cities and does not avoid agricultural land. The species is distributed from sea level to heights of over 3000 meters. The Northern Fiscal Shrike is an opportunistic hunter who goes after any animal it can overwhelm. Arthropods make up the majority of the diet. When there is a large supply of food and as evidence of the success of the hunt in the pairing season, prey is impaled in thorn bushes.

Lanius humeralis is a resident bird. Outside of the breeding season he wanders around in small areas; vertical migration has also been observed. He lives singly or in pairs. At least during the breeding season, the pair will claim territory.

The species , of which three subspecies are described, belongs together with the southern fiscal strangler to the Lanius collaris - superspecies . The extent to which other stranglers should also be included in this species group ( rust -mantled shrike , Mackinnon shrike , São Tomé shrike ) is the subject of current research.

This type of strangler has adapted very well to the proximity of humans in the region, is widespread and common locally. The species that benefits regionally from the destruction of rainforest areas is not listed in any endangerment category.

Appearance

Northern fiscal strangler, probably subspecies capelli - females
In this subspecies the reddish-brown flank feathers are usually not developed

The Northern Fiscal Shrike is a medium-sized to large, long-tailed, striking black-and-white strangler with a completely black head and neck. The size of the individual subspecies is between 21 and 23 centimeters with a weight between 35 and 39 grams. In the seated bird, the V-shaped shoulder and back markings are particularly noticeable and distinctive, while in the flying bird the sickle-shaped white wing fields, the light gray rump and the white outer feathers of the tail are additional .

The head, neck and upper back are jet black. The shoulder girdle is white, the rump whitish-gray to light gray. The wings are black. The white hand wings at their base form a not always clearly recognizable white wing field in the sitting bird, which is very conspicuous as a sickle-shaped marking in flight. The middle feathers of the long, narrow, stepped tail are black, the outer feathers - to the extent that varies between the subspecies - white or black and white banded. The underside is white or gray-white; Fine dark corrugations can be seen on the flanks, especially in the case of individuals that have just been colored. The mighty hooked bill is black, as are the legs. The iris of the eyes is blackish brown.

Males and females are colored very similarly. The black parts of the female plumage are less saturated, rather very dark black-brown. Characteristic is a fluffy, reddish-brown feather section on the flanks, which, however, is often hidden under the wings. Females are slightly smaller than males, and cannot be evaluated by field ornithology. Juveniles have a reddish-brown, densely dark wavy upper side, with the already white shoulder area also being black wavy. The head and neck are dark brown. The black face mask typical of a strangler, which is invisible in the adult bird due to the black of the head, is recognizable as a dark area around the ear covers . The matt white underside shows fine dark waves, sometimes also spots, the flanks are covered in reddish brown in both sexes. The wing field is matt white, often isabel colored. The large arm covers have a light brown border, a feature that can also be observed in one-year-old individuals. Juveniles in the northern group differ significantly from those in the southern group. The latter are rather gray-brown and only very finely wavy.

Occasionally, partial albinos have been observed.

Mauser

Juveniles begin to moult into their first adult plumage around three months of age . It is a complete moult that apparently takes place very quickly (within a month). The light edges of the large arm covers, occasionally also rust-brown feather areas on the flanks, can occasionally be detected even after the second total moult. Adult birds molt their entire plumage once a year after breeding. The time of the moult varies according to the regionally different breeding mines, with a peak in the respective dry seasons .

Vocalizations

The vocalizations of the representatives of the two species Lanius humeralis and L. collaris differ significantly. Panov, for whom molecular biological results were not yet available, saw this as an indication that at least two species can be distinguished in the Lanius collaris complex. The calls and chants of L. humeralis and L. smithii are very similar, while those of L. capelli show stronger similarities to the vocalizations of the representatives of the southern group.

The most important alarm call, which is used in various dangerous situations but also in interspecific disputes, is a noisy, hoarse, largely avocal hissing and croaking. In addition, a long whistle call (like djööö ... djöööö - strung several times) can be heard, which has no equivalent in the southern group. Contact and presence call is a melodious, moderately loud, polyphonic Djüö-dö with a falling pitch . Most of the varied and modulated series of calls are two-syllable, occasionally also three-syllable. They are particularly noticeable in the pre-breeding season; they are performed by both sexes, occasionally also in alternation. In addition, a number of other, mostly hoarse and harsh alarm and aggression calls can be heard, some of which are used very selectively in narrowly defined situations (e.g. warning of flight enemies). The singing is also a quiet, sometimes melodious warbling, in which whistles and sound imitations are embedded.

distribution and habitat

Distribution of the Lanius collaris - super species
red: Northern fiscal strangler
green: Southern fiscal strangler
dark blue: Reichenow crusher

L. humeralis is represented in three subspecies in Africa north and south of the equator. The northern limit of the distribution area is in the west at about 15 ° N in the border area between Mauritania and Senegal , in the east at about the same geographical latitude in Eritrea . The breeding areas north of the equator are split up like islands with occurrences in southern Mali , in the border area between Benin and Niger , in central Nigeria and the northern Central African Republic . Further, so far not proven occurrences in the Sahel are likely. Large closed distribution areas are in Upper and Lower Guinea and in the east in Eritrea, east-central and southern Ethiopia and in the southwest of the Republic of South Sudan .

The distribution areas around and south of the equator are more closed. They extend from southern Gabon and the central and southern part of the Republic of the Congo , with the exception of the rainforest areas over large parts of the Democratic Republic of the Congo , and across Uganda , central, southern and western Kenya , to the north and west of Tanzania . Towards the south, the species colonizes suitable habitats in Angola , almost all of Zambia and the north and northwest of Mozambique .

The distribution areas of the northern and southern groups only overlap in southwestern Tanzania, north of Lake Malawi , where L. humeralis capelli and L. collaris marwitzi occur together. There were evidently hybrids observed, but the information is about contradictory.

Open landscapes with trees and bushes and areas with little or no vegetation are preferred habitats of the species. Here the Harenna Forest in Central Ethiopia , where the species reaches the eastern limit of its distribution.

In this both topographically and climatically heterogeneous distribution area, the species is able to use a multitude of different habitats and shows a strong willingness to colonize anthropogenically modified landscapes. Since the early 1900s, the species has become more common in many regions.

The northern fiscal strangler occurs in semi-deserts, acacia-lined savannas and miombo -type savannas as well as in coastal bushland and bush-lined edges of marshes . It is a frequent breeding bird on the edge of agricultural land, in larger gardens, parks and golf courses as well as on the edge of plantations. However, the species avoids deserts and the interior of denser forests, as does gallery forests along the major rivers. Even pure grass savannahs are only populated in the peripheral areas or for a short time after extensive grass fires.

The vertical distribution ranges from coastal areas near sea level to high altitudes of 3000 meters and above.

Important requisites for a suitable territory are, in addition to sufficient food, perches on trees, bushes, termite mounds, pasture fences or telegraph poles and short or missing ground vegetation in order to be able to spot suitable prey. The lack of food competitors also plays a decisive role in the occupation of a territory. Where other shrikes, particularly the long-tailed shrike or the yellow-billed shrike , or European migrants ( gray shrike , red-backed shrike ) are often differs L. humeralis is usually sufficient.

The pairs usually maintain a territory throughout the year, the size of which depends on the food supply and the availability of hides. In agricultural areas of Ghana and in the vicinity of settlements, the average size of the districts was only 0.59 hectares; Territory sizes of up to 18 hectares were recorded in regions that were apparently much less nourished. There is a direct connection between the annual amount of precipitation and the size of the area: the drier the habitat, the larger the areas become. The smallest distance between two nests was 17 meters.

Biological details

Most of the scientific work on the biology of the Lanius collaris group concerns the southern subspecies. There are very few studies of the representatives of the northern group. As far as information is available, significant differences between the north and south groups are noted.

behavior

Like all stranglers, L. humeralis is diurnal. The activity time roughly corresponds to the brightness of the day. The stranglers usually live in pairs, whereby the pair bonds can last for several years. Young birds can briefly come together to form loose groups. The females, in particular, are extremely faithful to their location, only unmated roam small areas. Young birds also try to establish a territory close to their place of birth. Small scale migrations to dry areas were observed during the southern winter in Kenya.

Single males and couples claim and defend a territory. The readiness to defend is particularly intense in the pre-breeding and breeding season. During this time, conspecifics and other stranglers are not tolerated in the area, and competitors for food are also aggressively approached and driven away if possible, even if they are larger (e.g. Halcyon senegalensis ). Gray-coated shrike and northern fiscal shrike occur sympatricly in some areas and occupy neighboring areas. There is great aggression between species. When food becomes scarce in the dry seasons, the conflicts between the species often lead to L. humeralis leaving its territory.

The adult birds give intensive warnings of soil enemies and nest robbers, often with the participation of conspecifics from neighboring areas, and if possible they flee from predators in dense thickets. Disputes with conspecifics are usually carried out at the territorial boundaries by calling series. In an upright posture, the feathers of the white V-drawing are displayed. Highest level of interspecific aggression are tail circles hump attitude, wherein the beak under beak squire points to the opponent, and tracking flights. Contact fights are very rare.

Extensive sunbathing was found to be the main comfort behavior; Mutual plumage care was also occasionally observed.

Food and subsistence

The food of the species consists predominantly of insects, among which locusts occupy a preferred position. Beetles , including poisonous oil beetles , real crickets and mole crickets , butterflies , caterpillars and dragonflies also play an important role. To a lesser extent, ants , termites , bedbugs and cicadas , bees and bumblebees serve as food. The species also occasionally prey on worms , spiders , millipedes and crabs . Among the vertebrates , songbirds and their nestlings, as well as small rodents, are the most important prey. L. humeralis also overwhelms frogs , young snakes and lizards , geckos , chameleons and bats . Remnants of human food are eaten as well as occasional carrion.

Like most species of shrike, the Northern Fiscal Shrike can use different hunting methods, but high seat hunting is by far the preferred hunting strategy. Anything that rises above the surrounding earth's surface by more than a meter can serve as a hide . Mostly these are trees or bushes, termite mounds, pasture fences or telegraph poles, but occasionally also wild or grazing animals. The preferred heights are between 3 and 4 meters. A wide area can be overlooked from such a viewing point; the most effective hunting distance is within a radius of 10 meters. If the shrike spies a prey, it slides from the hide and hits it on the ground. If it can escape in the first attack, it is usually not pursued or only pursued very briefly. Smaller prey are immediately eaten on the ground outside of the breeding season, while larger ones are carried to a control room and consumed there. Prey animals that cannot be eaten in one piece are skewered or pinched and cut up piece by piece. The species also creates supplies by pinching or impaling, a behavior that is common among many stranglers, but was less frequently observed among representatives of the southern group.

In addition to high-seat hunting, these stranglers sometimes hunt on the ground or in flight. Brief periods of shaking and immersion in shallow water while hunting for tadpoles have also been observed. Occasionally, especially in very bad weather, prey animals are read from leaves or branches.

Breeding biology

L. humeralis has a monogamous long-term partnership that can last for several years. However, partner and territory changes during the breeding season do occur. The species becomes sexually mature at one year of age and at this age it usually begins its first brood. Two broods, occasionally three, are the norm.

During the pairing, the male can often be seen shouting loudly in an upright position and with ruffled chest and crown feathers in exposed areas of his territory. Chases from bush to bush and aggressive sitting opposite each other in a hunched position lead to the final pair formation with ritualized nesting and nest hollows, begging rituals of the female with food handover and finally copulation.

The breeding seasons vary greatly. Usually the mating season begins towards the end of the dry season or with the onset of the main rainy season , in West Africa at the end of February in the east a little later (March, April). In the tropical areas of Central Africa, fresh broods can be found almost all year round.

The final decision on the nest location seems to be made by the female, who also does most of the nest-building work. The nests are preferably in dense, thorny bushes at a height of about 3 meters, but the variation in nest locations is very large. The nest is an often misshapen structure made up primarily of twigs, stems and blades of grass using many other materials. The outer diameter can be up to 180 millimeters, the depth of the bowl varies between 35 and 75 millimeters. It will be built within a week.

With up to three eggs, the clutches are smaller than those of the southern group. The eggs are almost exclusively incubated by the female, who is fed by the male during this time, but occasionally also looks for food herself. The young hatch naked and blind after 14–15 days. They fledge after about 20 days. The tour lasts about a month, during which the young birds are fed with decreasing intensity. The young birds of the northern fiscal strangle remain in the family for up to 7 months. The breeding success is low due to the effects of often unfavorable weather conditions and due to the large number of nest predators . At least regionally, it does not seem to exceed 20%. There is an average interval of 3.7 months between two broods.

Systematics

In 2011, Jérôme Fuchs et al. in the Journal of Biogeography a study that confirmed on a molecular genetic basis what has long been suspected on the basis of behavioral and morphological findings, namely that several species are involved in the Lanius collaris complex. Following these research results, the IOC separated the complex into two types: a northern group with Lanius humeralis as the nominotypic taxon and a southern group with Lanius collaris as the nominate form .

The southern group with 4–5 subspecies is genetically homogeneous, despite some clear morphological differences. The three subspecies of the northern group, on the other hand, show relatively large genetic differences, so that further research is necessary in order to be able to define their taxonomic position more precisely. The main question is whether L. h. capelli is not to be understood as an independent species. The genetic distance between the north and south groups is greater than that between some taxa that have long been established as a species.

The rust -mantled shrike is the sister species of the southern group; the São Tomé shrike and the Mackinnon shrike, which in turn are sister species, are also closely related.

• Lanius h. smithii ( Fraser , 1843) : West and Central Africa north of the equator. East to the southwest of the Republic of South Sudan and western Uganda. Small distribution island within the distribution area of L. h. capelli south of the equator in the province of Cabinda . Shiny black top, pure white bottom. The females have no rust-brown color on their flanks or are only weakly developed. Outer feathers of the very long tail pure white.
• Lanius h. humeralis Stanley , 1814 : Mountain regions in East Africa. Matt black top, washed-out white underside. The outer feathers of the long tail are white. The females are clearly rust-brown on the flanks.
• Lanius h. capelli ( Bocage , 1879) : Mainly south of the equator (southern Gabon, Angola, northern Namibia, central and southern parts of the Republic of the Congo, Democratic Republic of the Congo, Uganda, central S and western Kenya, N and western Tanzania, Zambia, N- and NW Mozambique). Similar to humeralis , but less white on the outer tail feathers. No rust-brown flank coloring in the females.

Persistence and Threat

Qualitative and quantitative surveys are neither available at regional nor at supraregional level. The species is - to an increasing extent in settlements and cities - as common, but at least as widespread. In East Africa it seems to occur in higher numbers in the high areas than in the lowlands. In the extreme northwest of its range it is rare. Due to its very large distribution area, the stable or increasing breeding population and the lack of current threats, the IUCN classifies the entire population of Lanius collaris as (= least concern - not endangered).

The considerable natural losses due to weather influences, collisions with vehicles and natural enemies (above all various birds of prey and owls , crows and other stranglers , as well as snakes , monitor lizards , house cats, stealthy cats and monkeys , as well as due to brood losses due to the not inconsiderable brood parasitism of various cuckoo species ), can be well compensated by multiple broods. Direct persecution by humans has not yet played a role in limiting the population, but the increasing use of insecticides could have a negative impact on the population in the long term.

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 .
• R. Yosef & International Shrike Working Group (2016). Common Fiscal (Lanius collaris). 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/60490 on July 9, 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

1. ↑ ^{a b c} 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). Pp. 1-13
2. ↑ ^{a b c d e f g} T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 174.
3. ^ CP Kofron and A. Chapman: Deforestation and bird species composition in Liberia, West Africa . In: Tropical Zoology 8; 2; Pp. 239-256.
4. ^ BirdLife International. 2012. Lanius collaris. The IUCN Red List of Threatened Species 2012: e.T22705074A39383043. doi : 10.2305 / IUCN.UK.2012-1.RLTS.T22705074A39383043.en
5. ^ T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 177.
6. ↑ ^{a b c d e} T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 173.
7. ↑ Recordings at xeno-canto
8. ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, pp. 219–226.
9. ^ ^{A b} E. N. Panov: The True Shrikes (Laniidae) ... 2011, p. 225.
10. ↑ ^{a b c d e f} T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 175.
11. ↑ Author's note: The Reichenow shrike, which some authors consider to be an independent species, shows only a very small genetic difference to Lanius collaris , so it is its subspecies.
12. ↑ 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). Pp. 9-10
13. ^ Reuven Yosef & International Shrike Working Group (2016). Uhehe Fiscal (Lanius marwitzi). 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/60492 on July 11, 2016).
14. ↑ 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. 9
15. ↑ ^{a b c} Reuven Yosef & International Shrike Working Group (2016). Common Fiscal (Lanius collaris). 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/60490 on July 11, 2016).
16. ↑ ^{a b} M.A. Macdonald: The ecology of the Fiscal Shrike in Ghana, and a comparison with studies from Southern Africa . In: Ostrich 51: p. 68
17. ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 198.
18. ^ S. Zack and DJ Ligon: Cooperative Breeding in Lanius Shrikes. Habitat and Demography of two sympatric species. In: The Auk 102: 754-765. October 1985. p. 758
19. ^ Angela Chapman: Breeding and moult of four bird species in tropical West Africa. In: Tropical Zoology, Volume 8, Issue 2, 1995 pp. 227-238
20. ^ MA Macdonald: The ecology of the Fiscal Shrike in Ghana, and a comparison with studies from Southern Africa . In: Ostrich 51: p. 67
21. ^ T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, pp. 174-175.
22. ^ MA Macdonald: The ecology of the Fiscal Shrike in Ghana, and a comparison with studies from Southern Africa . In: Ostrich 51: p. 69
23. ^ T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 176.
24. ^ MA Macdonald: The ecology of the Fiscal Shrike in Ghana, and a comparison with studies from Southern Africa . In: Ostrich 51: pp. 69-70
25. ^ MA Macdonald: The ecology of the Fiscal Shrike in Ghana, and a comparison with studies from Southern Africa . In: Ostrich 51: p. 70
26. ↑ World Bird Names IOC 6.2
27. ↑ 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). Pp. 8-10
28. ↑ 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
29. ↑ 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. 2
30. ↑ LP Quinn, B, J. de Vos, M. Fernandes-Whaley, C. Roos, H. Bouwman, H. Kylin, R. Pieters and J. van den Berg: Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa pdf engl.