Chess strangler
| Chess strangler | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chess Shrike ( Lanius schach ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Lanius chess | ||||||||||||
| Linnaeus , 1758 |
The chess shrike ( Lanius schach ) is a songbird from the genus of the real shrike ( Lanius ) within the family of the shrike (Laniidae). The medium-sized, conspicuously long-tailed shrike species (English name: Long-tailed Shrike) has a very large distribution area that extends from Central Asia over the entire Indian subcontinent , central and southern China , almost all of Indochina , the Malay Peninsula and the Philippines to far extends into the Indonesian island world . With its occurrence in southeastern New Guinea , it is the only species of strangler of the Australis . Corresponding to this extensive, both climatically and topographically highly differentiated distribution area, many subspecies have been described, nine of which are currently generally recognized.
Most chess shrikes are largely resident birds , only the most northerly distributed populations regularly leave the breeding areas and move to southern or southeastern areas.
The differences in color between the subspecies are considerable. A distinction is usually made between two groups: the gray-headed subspecies, in which the typical face mask is clearly recognizable, and the black-headed chess shrike, in which the face mask is assimilated by the rest of the head color. There is also a melanistic morph from Lanius schach schach which is exclusively black, gray-black and gray in color.
Long-tailed shrike feed mainly on insects and other invertebrates , but the diversity of prey species - among them besides various small vertebrates and crustaceans , molluscs and small fish - larger than other shrike species.
The relationship of the species within the East Palearctic representatives of the genus has not been sufficiently clarified. The Tibetan shrike is considered to be a very closely related species and is also considered conspecific by some taxonomists .
The name Schachwürger, or Lanius schach, refers to a frequently heard alarm call of the species, which Pehr Osbeck chose for the species in 1757 and which was taken over by Carl von Linné a year later . The type specimen comes from the Guangdong area .
Although population analyzes are completely lacking for many distribution areas, none of the subspecies is listed by the IUCN in a risk level (LC = least concern ).
Appearance
_in_Kolkata_W_IMG_3434.jpg)
.jpg)
_-_Flickr_-_Lip_Kee.jpg)
_juvenile_-_Flickr_-_Lip_Kee.jpg)
Among all types of shrike, the chess shrike shows the clearest differences in color between the individual subspecies. The differences in size and weight can also be considerable: Lanius s. caniceps , one of the smallest subspecies, measures around 23 centimeters and weighs between 33 and 38 grams, the nominate form, on the other hand, reaches a size of up to 27 centimeters and a weight of up to 61 grams. Also the tail length is not remarkably large in comparison to the wing length in all subspecies: In the comparatively short-tailed L. s. erythronotus the ratio is 1: 1.23, in the extremely long-tailed subspecies L. s. longicaudatus on the other hand 1: 1.55.
Harris and Franklin divide the chess stranglers into two groups according to their main characteristic, the head color: The gray-headed subspecies include L. s. schach , L. s. erythronotus and L. s. caniceps , the black-headed L. s. longicaudatus , L. s. tricolor , L. s. nasutus , L. s. suluensis , L. s. stresemanni and L. s. needed . The latter forms a transitional form between these groups in terms of coloration. Panov differentiates even more and defines three groups.
There are only very slight differences in color between the sexes in both groups. Females of both groups sometimes show slight banding, especially on the upper side, and are imperceptibly less intensely colored. Only a few sizes and weights are available, for some subspecies they are completely absent; the data available may indicate minimal dimorphism in favor of the males.
Gray-headed subspecies
The head, neck and coat are gray in different intensities and depths of color. The black face mask runs from the forehead over the eyes to behind the ear covers. The gray of the coat merges into the reddish brown of the back and rump. The wings are black, with the umbrella feathers and the arm feathers edged in cinnamon brown. The base of the inner hand wings is white, which creates an almost always recognizable small white wing mirror when the bird is sitting, and a distinctive, sickle-shaped wing field when it is in flight. The stepped tail is dark brown, the outer control feathers are a little lighter. The throat, chest and belly are usually pure white or matt white, the flanks clearly exuded reddish brown. The iris is black, as is the mighty hooked bill. Legs and toes are dark gray. The black morph of L. s, which occurs relatively frequently in Southeast Asia and on Taiwan and Hainan, has a special position . schach (sometimes incorrectly listed as L. s. fuscatus subspecies ). It is dark gray, almost black, on the upper side, also slightly black-brown towards the rump, and a little lighter gray on the lower side. The extensive black face mask stands out clearly from the otherwise rather light head plumage.
Black-headed subspecies
In these subspecies, the entire head, the neck and partly also the uppermost areas of the coat are deep black. A face mask cannot be seen. Towards the back, the coat either tends from gray to an intense reddish-brown or is entirely reddish-brown, usually darker and more saturated than in the gray-headed subspecies. The wings are black, the cinnamon-brown edge of the umbrella feathers and hand wings is very clear. The white wing field is also usually relatively large and distinctive. The especially with L. s. longicaudatus very long tail is thin and black. The underside as well as the featherless body parts resemble those of the gray-headed subspecies.
Youth plumage
The coloring of chess stranglers in their first youth dress is not as different between the two groups as it is in adults . Young birds of both groups are predominantly gray on the upper side with increasingly brownish tones towards the coat and back. The wings are black and usually have a cinnamon-brown edge, as in adult birds. Young birds of both groups are wavy blackish on the upper side, those of the gray-headed subspecies slightly more intense. The black face mask is very clear in later black-headed young birds, in those of the gray-headed group it is paler and often only recognizable in the area behind the eyes up to the ear covers. The white wing field is also clearly developed in the black-headed group, while it is very small or absent in the other group. The underside of the gray-headed young shrike tends to be yellow-brown in color and has variously distinct rust-red bands, while in later black-headed birds the chest and upper abdomen are mostly almost unbanded and matt white and only the flanks and the lower abdomen have rust-red color elements and light banding. The color of the tail is almost black in the gray-headed, brownish in the black-headed with significantly lighter outer feathers.
Mauser
Data on the extent and phenology of moulting are only available for some subspecies. According to this, adults seem to completely replace the plumage once after the breeding season. In migrant populations, the change of feathers in the large plumage is largely complete before they leave, in resident populations it seems to extend into the winter half-year for longer. The moulting of the young birds into the first adult plumage begins a few weeks after they fly out. She should mostly be a full moult. In the spring, however, yearlings with unmoluted wings were also found, so that in some populations or subspecies there are apparently different degrees of plumage changes before breeding season.
Vocalizations
The species is acoustically very present in the period of the establishment of the territory, but behaves very silent and hidden with the beginning of the breeding season and also afterwards. The most important vocalizations, i.e. the various alarm calls and the basic structure of the song, are not identical in all subspecies, but very similar. Due to the often extremely precise imitation of the songs and calls of other bird species, which are differently arranged and woven into the song in different ways, chess strangler chants are nevertheless very different individually and regionally. In an individual song, 13 phrases from other songbirds as well as railing and kingfisher calls were detected. The most frequent alarm call is a multiple row, screeching, rough, hoarse, quite loud ksha , which is also transcribed as sha , shah . In addition, more vocalized, two-syllable, somewhat quieter calls can be heard, which are interpreted as a presence signal. Other calls are reminiscent of those of the king corn or the quail . The singing is a sonorous, but quite voluminous, mostly melodic and rhythmically structured murmur and warble, interspersed with whistles and scratchy elements as well as with various vocal imitations. The singing can be heard by both sexes, that of the female is a little quieter and less structured.
distribution
Chess stranglers are from the macro coast of northeastern Iran and its hinterland, Afghanistan , Pakistan , and parts of the Central Asian states in the west over the entire Indian subcontinent and the northernmost regions of Sri Lanka northwards to the southern Himalayas , to the east over southern and central China and distributed almost all of Indochina to the coasts of the East China and South China Seas . The large islands of Hainan and Taiwan are also inhabited. To the south and southeast, the species inhabits the Malay Peninsula , all of Sumatra and the Sumatra offshore islands, parts of Borneo , Java , most of the islands of the Philippines , the islands of the Sulu Archipelago , most of the Lesser Sunda Islands and finally the southeastern mountainous region of New Guinea .
In the past 20 years, a slight northeast expansion of the species has been recorded along the northern foothills of the Tian Shan . In 2005 a pair brooded about 100 kilometers northeast of Lake Alaköl .
The chess shrike is represented vertically from sea level up to heights of about 3000 meters, exceptionally breeding occurrences up to 4300 meters have been found in the Himalayas.
habitat
Chess stranglers are very flexible in their choice of habitat and can therefore inhabit a large number of, sometimes very different, habitats. In addition to an adequate supply of food, however, trees or bushes are always essential as breeding grounds or hunting grounds . Sections of the terrain with short-grass vegetation are preferred, but are not an exclusive requirement. Chess stranglers also breed in extremely high-grass or reed-covered and relatively densely bushed areas and adapt their hunting methods accordingly.
The species inhabits, among other things, loosely bushy semi-deserts, light montane juniper stands, thorn forests , acacia savannas , steppe areas with tree islands on the edge of rivers or irrigation channels, windbreaks along roads or fields, pasture land, large orchards, parks and golf courses. It also occurs in the fringes of forests and plantations and populates wetlands such as raised bogs , marshes , bushy or tree-lined strips of land along rice fields and areas near the beach, if the vegetation allows. Especially in the northwest of the distribution area, the species has become used to the presence of humans and is also found in small rural settlements.
hikes
Only the northernmost populations are mostly migratory birds that leave their breeding grounds between August and November and move south or south-east. The wintering areas are in central and southern India, in Bangladesh and in northern and central Indochina. Occasionally, however, chess stranglers that had drifted away were found far away from the usual winter spots: once in Israel and several times in Japan . Breeding birds at higher elevations migrate to climatically favored or lower-lying areas. Depending on the location of the breeding areas, the first migrants will return as early as the end of February. The vast majority of chess stranglers are present in the breeding area all year round.
Space requirements
The few data on the size of the territory and space requirements of the species indicate no significant differences to other medium-sized Lanius species. In optimal breeding habitats the species can reach very high population densities, for example in the outskirts of Kabul , where 8–12 breeding pairs are counted per square kilometer, or in other areas of Afghanistan and Turkmenistan, where even up to 4 breeding pairs per hectare , or 26 pairs 7 hectares were identified. The minimum nesting distance in habitats in which the species breeds in so-called territorial clumps is less than 100 meters. However, the average population density is much lower, the nest spacing and area sizes are correspondingly larger.
Food and subsistence
Like most shrike species, the chess shrike is a highly opportunistic hunter who selects his prey according to the best possible energy efficiency. Mostly these are relatively large insects , such as grasshoppers , catching horrors , crickets , cicadas , beetles , butterflies and their caterpillars , dragonflies and hymenoptera , including stinging species. Other invertebrates such as earthworms and millipedes , as well as arachnids such as scorpions, are also eaten. Small vertebrates such as birds, mice , small lizards , agamas and geckos , frogs and fish as well as crabs and other crustaceans are of different importance for the energy supply of the species depending on the habitat and possibly also depending on the season. Nestlings always seem to be a not insignificant part of their diet: chess stranglers also attack relatively large species such as the almost completely feathered nestlings of the palm pigeon and overwhelm them, or systematically take out the nests of colony breeders such as the house sparrow or the willow sparrow .
Chess stranglers hunt and beat all types of overwhelming small birds to varying degrees; in some populations, birds are an essential source of food, especially when rearing young. Nutmegs seem to be captured particularly frequently. Chess stranglers have occasionally been observed ingesting fruits and berries, especially those of the neem tree .
The preferred hunting method is high seat hunting. From an elevated viewing point, the shrike overlooks a sector between 10 and 15 meters and searches it for suitable prey. If it spies one, it glides from the hide, usually accelerates with a few flaps of its wing and hits it on the ground. Usually he carries the victim back to the exit control room and eats it there. Often he changes his hide after trying to hunt. This energy-saving acquisition of prey is only possible in the absence of barren or very low vegetation, but is also retained in modified form in other vegetation structures, only the prey is not struck on the ground, but on stems, blades of grass, leaves and other surfaces - even in very shallow water . In addition, chess stranglers systematically search substrate surfaces for prey, occasionally hunt in a kind of flutter-hopping on foot, and - especially when there is a large supply of flying insects - in the air. Chess stranglers can occasionally beat small birds, even fliers as skilful as swallows, in the air. Apparently, they take advantage of situations in which the potential victim is only able to react to a limited extent, such as when taking off or landing. Kleptoparasitism was found in some cases . Some subspecies create supplies by impaling and pinching prey, but it is currently not known whether this behavior is developed in all subspecies.
behavior
Chess stranglers are territorial throughout the year. They are considered robust and combative. In the pre-breeding season they defend and maintain their entire breeding and feeding area intensively, during the breeding season and later only the immediate area around the nest location and the storage areas. The most important elements of the territorial display are loud calls made in an upright posture at exposed points in the territory, low sightseeing flights interrupted by fluttering and gliding phases along the territorial boundaries, and in actual disputes with conspecifics or other opponents, the threatening gestures typical of stranglers, such as humpbacks with spreading tails, Swinging the head, flapping wings and pointing the beak - in extreme cases, however, also direct approach with body contact. If humans or predators come too close to the nest, chess stranglers remain silent for a very long time, but if they come too close they try either to tempt the intruder or attack him directly. Females usually only take part in the arguments vocally. They flee from flight enemies in dense undergrowth, nest robbers or brood parasites attack them directly and also mob them outside the territorial boundaries.
Most of the subspecies are exclusively diurnal. Only some populations in southern China that have specialized in hunting crabs that only appear at night also hunt in the first hours of the night on bright nights.
Breeding biology
As far as known, chess stranglers lead a monogamous season partnership. It is not known whether and with what frequency a loose pair bond remains outside the breeding season. In migrating populations, it is not uncommon for pairs to return to the breeding area already paired and immediately begin to establish a breeding area. The breeding seasons for most of the subspecies are between February and August. With moving chess stranglers and those with breeding areas in very high altitudes, the breeding peak is in May and June, birds of the subspecies stresemanni breed between June and November, while those of the subspecies needed fresh eggs were found throughout the year. Pairs that nest in relatively high latitudes and in high-lying areas only breed once a year, with breeding birds in more southern areas, especially those in the Indonesian islands and in Wallacea , two broods - occasionally three broods - are the rule.
_at_Nest_in_Kolkata_I_IMG_8257.jpg)
L. s. erythronotus often builds its nests in trees ( poplars , mulberry trees , milk orange trees ) at heights between 3 and 4 meters, in settlements where the species often nests, usually a little higher. Acacias are frequent nest carriers in arid regions . The subspecies L. s. chess often breeds in bamboo stocks , L. c. caniceps and L. s. needed in palm trees , nests of L. s. nasutus are often in mango trees and imported in the Philippines locust found. L. s. stresemanni prefers to build its nests in tall grass. Overall, however, all types of available bushes and trees and also grasses can be considered as nest locations, provided they have a minimum height and sufficient load-bearing capacity. The nest distance from the ground is very variable: nests can be built almost close to the ground, but also at heights over 20 meters. Chess strangler nests between 3 and 5 meters are most common.
The nest is built in 6–8 (4–7) days, with both partners collecting the nesting material but the female doing the main construction work. The load-bearing framework of the nest is made up of stems and twigs and is woven with grasses, often with various plastic waste, and firmly wedged in a fork, usually near the main trunk. Inside it is a bowl made of finer materials, particularly fine blades of grass, moss, plant and animal wool. Some nests look very untidy and unstable from the outside, but they are usually very resistant constructions that can withstand the not uncommon strong winds in the breeding areas. The outer diameters of the nests vary greatly, but the inner diameter is usually between 70 and 95 and the depth of the bowl between 50 and 65 millimeters.
The clutch consists of 3–4 (2–8) eggs of variable color, often matt white or greenish-white tinted eggs, which often have an intense rust-red, violet or gray-brown color at the blunt end. Their size is quite uniform and averages 22.5 x 17.9 millimeters. The largest clutches are found in breeding birds at high latitudes, the smallest, with an average of only two eggs, in the subspecies L. s. stresemanni in New Guinea.
The incubation period is 13–16 days, the nestling period is 14–19 days. When leaving the nest, the nestlings are only capable of short fluttering flights and remain in the immediate vicinity of the nest for a few days. It mainly breeds by the female, and can only be briefly detached from the male. This provides most of the food for the nestlings and the female. In the nested broods that occur frequently , the male looks after both the female already sitting on the new clutch and the young birds of the previous brood that are still to be led. Young birds begin to beat prey on their own around the age of 25 days, but stay with the family for at least 10 weeks.
Systematics
The relationship of the species within the genus Lanius is not completely clear. A small Chinese study that only considers 8 East Asian species found 5 subspecies of the chess shrike in a clade with the Burmese shrike . This in turn is closely related to the Tibetan shrike, buffalo head shrike and brown shrike . The taxonomic rank of some of the nine currently recognized subspecies is also under discussion.
The subspecies differ significantly in terms of color, size, and wing and tail length.
- Lanius schach schach Linnaeus , 1758 : Central, South and Southeast China, Taiwan, Hainan, Vietnam ( Tonkin and Annam ). Gray-headed; wide face mask, relatively little gray on the back. Lanius s. chess hybridizes with L. s. tricolor . Intermediate colored birds are mainly found in north-western Myanmar. In the south of the range and on the islands of Hainan and Taiwan, birds of the dark morphine occur, which are gray-black and black in color. They mix with regularly colored chess stranglers, whose offspring have yellowish and reddish-black hues in addition to the gloomy gray color elements. The assumption that this is a separate species L. fuscatus has been refuted by molecular genetic studies.
- Lanius chess erythronotus ( Vigors , 1831) : Südostkasachstan , southern Uzbekistan , Kyrgyzstan , Südturkmenistan , Tajikistan , Afghanistan and Pakistan, east to northern and central India; probably northeastern Iran as well. Gray-headed; white border of the black face mask, gray on the back somewhat more extensive than in L. s. chess . Lanius s. erythronotus hybridizes with L. s. tricolor . Intermediate colored birds are found from the northwestern Himalayas south-southeast to Odisha on the Bay of Bengal . These mostly black-headed shrikes are sometimes called the L. s subspecies . nigriceps led.
- Lanius schach caniceps Blyth , 1847 : Southern and Western India, Northern Sri Lanka. Gray-headed; Mostly gray on the back, very wide face mask, small white wing field, often covered when sitting.
- Lanius schach longicaudatus Ogilvie-Grant , 1902 : Central, Southeast and Southern Thailand , Southern Laos , possibly Southern Myanmar . Black-headed; Blackening up to the neck and upper coat. No gray on the back; large white wing field; Throat and chest with reddish brown air; extremely long tail.
- Lanius schach tricolor Hodgson , 1837 : Nepal and East India, eastward to northern Myanmar, western southern China ( Xizang and Yunnan ), northern Thailand and northern Laos. Black-headed; mostly only little or no gray-black in the upper coat area, rest of the coat and back fawn-brown, small wing field, often hidden when sitting, slightly shorter tail. Throat, chest and stomach pure white.
- Lanius schach suluensis Mearns , 1905 : Southern Philippines and Sulu Archipelago. The three island races suluensis , nasutus and stresemanni are very similar to each other and only differ in the amount of gray color on their backs. Black-headed; similar to the subspecies tricolor , but a little paler and with a little gray on the lower coat.
- Lanius schach stresemanni Mertens , 1923 : Southeastern mountainous region in New Guinea. Black-headed; overall darker, deeper rust-red on top; Gray of the mantle more extensive than that of Suluensis .
- Lanius schach bentet Horsfield , 1821 Malay Peninsula, Sumatra, Java, Lesser Sunda Islands east to Timor . Black-headed, but often with a gray crown and neck so that the face mask is recognizable. Is considered an intermediate form of gray-headed and black-headed subspecies. Birds from Southeast Borneo, East Java and Bali are often very different, so there may still be a subspecies here.
Persistence and Threat
The chess shrike lives in a very extensive area in which it is a frequent breeding bird in some areas. Exact stock figures and population trends are not available. According to the IUCN, the species is currently not endangered. It can expand its breeding area in the northwest of its range and in some parts of Southeast Asia, where the deforestation of the primary forests of the species opens up new habitats. Nevertheless, it seems to be rarer in the western part of its breeding area, or to be subject to large cyclical fluctuations. In most countries the chess shrike is a protected species, in some it is listed as an endangered species. In addition to natural enemies such as various birds of prey , martens , civets , crows, snakes and lizards, chess stranglers are also persecuted by humans in some regions. Different types of cuckoo regularly parasitize chess stranglers.
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 .
- Josep del Hoyo , Andrew Elliot, Jordi Sargatal (Eds.): Handbook of the Birds of the World. Volume 13: Penduline-Tits to Shrikes. Lynx Edicions, Barcelona 2008, ISBN 978-84-96553-45-3 .
- R. Yosef, E. de Juana, International Shrike Working Group: Long-tailed Shrike (Lanius schach). In: J. del Hoyo, A. Elliott, J. Sargatal, DA Christie, E. de Juana: Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona 2013. ( online November 25, 2014).
- 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 R. Yosef, E. de Juana, International Shrike Working Group: Long-tailed Shrike (Lanius schach). In: J. del Hoyo, A. Elliott, J. Sargatal, DA Christie, E. de Juana: Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona 2013. ( online November 25, 2014).
- ↑ a b Lanius schach in the IUCN Red List of Endangered Species 2014.2. Listed by: BirdLife International, 2012. Retrieved November 16, 2014.
- ↑ a b EN Panov: The True Shrikes (Laniidae) ... 2011, p. 680.
- ↑ a b c d e f g h i j k l T. Harris, K. Franklin: Shrikes & Bush-Shrikes… 2000, p. 209.
- ↑ a b c d e T. Harris, K. Franklin: Shrikes & Bush-Shrikes… 2000, p. 207.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, pp. 679-680.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, p. 696.
- ↑ a b c EN Panov: The True Shrikes (Laniidae)… 2011, p. 700.
- ^ T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, pp. 208-209.
- ↑ xeno-canto: sound recordings - chess strangler ( Lanius schach )
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, p. 688.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, p. 687.
- ↑ a b EN Panov: The True Shrikes (Laniidae) ... 2011, p. 686.
- ↑ a b c EN Panov: The True Shrikes (Laniidae)… 2011, p. 697.
- ↑ a b c d e T. Harris, K. Franklin: Shrikes & Bush-Shrikes… 2000, p. 208.
- ↑ a b c d Khoo Siew Yoong: Observations on the hunting and feeding behavior of breeding Long-tailed Shrikes Lanius schach. In: BirdingASIA 16 (2011) pp. 71-74.
- ↑ a b EN Panov: The True Shrikes (Laniidae) ... 2011, p. 698.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, pp. 113–115.
- ↑ a b c EN Panov: The True Shrikes (Laniidae)… 2011, p. 681.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, p. 86.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, p. 690.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, pp. 691–692.
- ↑ EN Panov: The True Shrikes (Laniidae)… 2011, pp. 691–693.
- ↑ a b Wei Zhang, Fu-Min Lei, Gang Liang, Zuo-Hua Yin, Hong-Feng Zhao, Hong-Jian Wang and Anton Krištín: Taxonomic status of eight Asian shrike species (Lanius): phylogenetic analysis based on Cyt b and CoI gene sequences. In: ACTA ORNITHOLOGICA Vol. 42 (2007) No. 2.
- ↑ a b EN Panov: The True Shrikes (Laniidae) ... 2011, p. 689.
