Tiger shrike
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Tiger shrike ( Lanius tigrinus ), above the male |
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| Lanius tigrinus | ||||||||||||
| Drapiez , 1828 |
The tiger shrike ( Lanius tigrinus ) is a songbird belonging to the genus of the real shrike ( Lanius ) within the family of the shrike (Laniidae). The rather small shrike species has a relatively limited range in the extreme southeast of Russia , on the Korean Peninsula , in northeast and eastern China and on some Japanese islands . In particular, the western borders of its distribution area are not sufficiently known, as the tiger shrike is one of the rather poorly researched shrike species.
Tiger stranglers are migratory birds , those in the northern areas of distribution sometimes long-distance migrants with wintering areas in southern Malaysia and the Indonesian islands .
Tiger shrike feed almost exclusively on insects; In their hunting methods, they differ significantly from other shrike species and their preference for more wooded habitats with dense undergrowth is shared by very few representatives of this genus.
The tiger shrike is monotypical . A few questions remain unanswered about its relationship within the genus, but it is usually placed in the closest relationship of the superspecies with red- backed shrike , Isabellian shrike and brown shrike . It shares some behavioral characteristics with the brown shrike and seems to be particularly closely related to it.
The name tiger shrike or Lanius tigrinus refers to the black banded (tabby) back plumage of the species. The type specimen comes from Java .
Although population analyzes are completely lacking for many areas of distribution and a clear population decline has been recorded for the Russian and some Japanese occurrences, the IUCN does not list the tiger shrike in any hazard level (LC = least concern ).
Appearance
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With a size of about 18 centimeters, the tiger shrike is as big as the red-backed shrike , with which it shares essential features with its reddish-brown, gray and white coloration. Tiger shrike , however, appear more massive than red-backed shrike, are a little heavier than these with an average of 28 grams, and their beak is significantly larger and thicker, which is also indicated by another common name in addition to Tiger Shrike with Thick-billed Shrike . The color dimorphism is quite clear, females are on average slightly lighter than males.
The crown, neck and upper part of the mantle are pale gray, sometimes slate gray, in male tiger stranglers. The black face mask extends from the upper beak base and runs over the eyes to behind the ear covers, it is sometimes bordered with white in the eye area. The lower coat area, the back, the rump and the upper tail-coverts are dark-rather dark brown and banded black-brown at quite wide intervals. The wings are dark brown, almost black; the umbrella feathers are a little lighter and some of the arm wings have a reddish brown border. The stepped tail is reddish brown, the outer feathers have a slightly lighter shade. The entire underside is matt white; especially in younger birds it shows a fine dark undulation especially on the flanks. The blue-black beak, black at the tip, is strikingly powerful, the legs and toes are gray-black, the iris is dark brown.
Females are generally paler in color, the gray parts of the crown, neck and upper coat are mostly interspersed with brown, the mask is only clear behind the eyes, in front of and at the base of the beak is often missing or only hinted at. The light stripe above the eyes is more noticeable in females than in males. The banding on the back, partly on the neck and head, is more prominent; the lower part of the abdomen and the flanks are particularly intensely banded and wavy.
The youth plumage is clearly darkly banded, wavy and sparrowed on the upper side on an almost uniform, matt brown background , and, especially in the head area, irregularly lightly dotted. A white eyelid border and the overlying light stripe over the eyes make young birds appear big-eyed. The face mask is not yet indicated. The underside is light and especially on the flanks densely dark wavy and banded.
Mauser
All tiger shrike change their entire plumage twice a year, a characteristic that they only share with the brown shrike in this genus. The first full moult begins immediately after the breeding season (usually as early as mid / late July) and ends with the move (late August / early September). Young birds appear in their first juvenile plumage in the wintering areas, adults in a plain dress that resembles the female plumage and in which the sexes are somewhat more difficult to distinguish. Between December and April juveniles and adults molt into breeding plumage.
Vocalizations
Like most stranglers, the tiger shrike is only noticeable acoustically during the establishment of territory and in aggressive situations. During the breeding season and afterwards the species is largely silent. Main alarm calls are a sequence of loud, very quickly (up to 10 elements / second) lined up, possibly with quei ... transcribable sound sequences that can be remotely reminiscent of calls from small falcons, especially if they are lined up individually or only slowly. In addition, almost vowelless Tsch (a) h calls can often be heard. The singing is typical of a strangler, rather muffled, persistent chatter, partly melodic and structured, partly also interspersed with croaking and hoarse noise elements. Voice imitations, which are an essential part of the song of many types of stranglers, are not known in the tiger shrike.
distribution and habitat
The distribution of the tiger shrike is limited to a comparatively small area in East Asia whose distribution limits are not exactly known, especially in the west of the breeding area. The core zones of the deposits are in northeastern China and apparently also on the Korean Peninsula. The breeding area extends, forming a semicircle, from about 43 ° north in the Ussuri area in the extreme south-east of Russia via Shaanxi and eastern Sichuan in the west to a little south of the mouth of the Yangtze River at about 29 ° north, after Lefranc even to close to the Tropic of Cancer . The tiger shrike also breeds on Honshu , Sado and Kyushu and the Korean Peninsula with the exception of the extreme south.
The wintering areas adjoin immediately to the south and extend over the entire south-east and south of China, over north Vietnam , north Laos , north and west Thailand and the east of Myanmar , the Malay Peninsula to Sumatra and its neighboring islands, Java and Borneo .
The tiger shrike is more tied to wooded areas than most of the other representatives of its genus. In the Ussuri area, where the species is only found in low densities, it inhabits subtropical mixed forest along relatively narrow river valleys and lowlands with more loosened trees, including Mongolian oak , Juglans mandshurica and elms . The edges of contiguous forests, extensive clearings with dense undergrowth or areas with large-scale logging are preferred. Tiger shrike can also be found in forest islands on the edge of cultivated land, in extensive orchards and occasionally in denser tree populations in large urban parks.
The species also avoids dry open land areas in the wintering areas. It inhabits the fringes of secondary or primary forests, arable land, mangroves and large gardens and parks with sufficient trees.
Tiger shrike are birds of the lowlands and hill countries. In the breeding areas nests up to heights of 800 meters were found; hibernating birds have been observed at altitudes of around 1000 meters.
There is hardly any data on settlement densities and area sizes. For the Ussuri area, Panov estimates a breeding pair to be 2.5–3 km², but he also found small clumps of territory in which the nest spacing was between 10 and 12 meters, which suggests small territory sizes under good conditions. Tiger stranglers can nest in the immediate vicinity of brown strangles and buffalo head shrikes without any notable conflict situations being observed.
hikes
With the exception of a few populations in Japan, all tiger shrike are migratory birds. Some only move short distances to the south or southeast, but others are long-distance migrants with train distances of several 1000 kilometers. The Russian breeding sites are cleared from the end of August, those further south a little later. At the ringing station on Fraser's Hill in northern Malaysia, migrating tiger stranglers are observed between the beginning of September and the end of October, and migrating tiger stranglers between the beginning of April and mid-May. The northernmost breeding sites are occupied again by mid-June at the latest.
Food and subsistence
Tiger shrike feed almost exclusively on invertebrates , especially insects . The young are also mainly fed insects. Small vertebrates such as mice , lizards, nestlings and small birds , as well as frogs are beaten on occasion, but do not play a major role in the species' energy needs. The largest possible types of insects predominate, especially beetles , grasshoppers , crickets , butterflies and their caterpillars as well as Schnabelkerfe . Investigations on young Korean birds revealed a food composition that consisted almost equally of larvae of a locust species and sex animals of cicadas . The rearing food for youngsters in the Ussuri area consisted almost exclusively of locusts, the heads of which were removed before feeding.
The hunting methods of the tiger shrike differ from those of most other species of shrike. Although he is also a waiting hunter where the vegetation allows it, this energy-saving hunt is often not possible in his habitat. The species obtains most of its food by systematically searching all strata of its habitat, from the shrub layer close to the ground to the top of the trees. It is not known whether tiger shrike create supplies by pinching or impaling prey.
behavior
Tiger shrike live largely solitary in the winter half-year, in pairs in the breeding season. They breed individually, usually with very large nest distances, but occasionally also in so-called territory clumps, in which the distances to the neighboring nest can be very small. They are diurnal and at least territorial during the breeding season. The territory is indicated by chants and calls, usually performed from the top of a tree, and delimited by slow, conspicuous sightseeing flights. The courtship begins immediately after arrival in the breeding area, sometimes breeding birds return to the breeding area already paired. The courtship rituals contain the typical elements of a strangler such as handing over food, murmuring chants with head swings, nodding and flapping of wings, showing suitable nest locations and sightseeing flights. The slow up and down movements of the tail are typical of the tiger shrike. Females beg for food in a crouched posture and the begging sounds of the nestlings, and in this position also ask for mating. Overall, the establishment of territory and pair formation take place within a few days.
Breeding biology
Tiger stranglers lead a monogamous seasonal partnership. They usually only breed once a year, but replacement clutches if the clutch is lost early are the rule. The breeding season begins in late May and lasts until mid / late July. Occasionally, brood aid was observed by unmated males. The nest is built by both partners in 5–7 days at heights between 1.5 and 5 meters, sometimes significantly higher. In contrast to the nesting location of other Palearctic shrike, it is usually not in the immediate vicinity of the main trunk, but in a fork in a strong side branch, often a few meters from the main trunk. Deciduous trees such as elms, oaks, birches and various wild fruit trees are frequent nest carriers, but occasionally nests are also built in bushes or in thorn bushes of various Rubus species. The nest is a relatively small, very carefully interwoven bowl, the basic structure of which often consists of interwoven mugwort stems , which are often also interwoven with bast fibers detached from pieces of bark. The inner layer consists of compactly interlocking blades of grass, panicles and moss. The inside of the bowl is lined with all kinds of soft materials such as plant wool and moss, and the outside is often covered with leaves and flowers. The average outside diameter is 120, the inside diameter 70 and the cup depth 45 millimeters. If a couple is disturbed while building a nest, or if a potential nest robber discovers the nest site, even almost finished nests are abandoned.
The clutch consists of 3 to 6, but mostly 5 matt white, greenish-white or greenish-bluish tinted eggs, which have gray, gray-brown or purple spots and spots, especially at the blunt end, of varying intensity. On average, they measure 21.2 × 16.4 millimeters. They are laid every day and only incubated from the last egg onwards, so that the young usually hatch within one day after around 14-16 days. Apparently only the female breeds when she is supplied with food by the male during the breeding season and in the first days of the nestling. The nestlings leave the nest, barely able to fly, after about 14 days; however, they remain in the immediate vicinity of the nest and are looked after by their parents for at least another two weeks.
Information on breeding success is not available. The most important nest predator is the magpie , many broods are lost due to strong winds or cold spells.
Systematics
The relationship of the tiger shrike within the genus, but especially within the Central and East Asian representatives of Lanius, is not sufficiently clarified. In the authoritative literature it is placed in the vicinity of the super species with red backed shrike, Isabellian shrike and brown shrike. Several documented, partially successful broods between brown shrike and tiger shrike, which occur in some areas of their range both sympatric and in the same habitats, suggest a close relationship between these two species. The study by Wei Zhang et al. indicates, however, an early separation of the development of the tiger shrike from those of the nine-killer, Isabel shrike and brown shrike.
No subspecies of the tiger shrike are described.
Persistence and Threat
There is no information about the total population of the species. Distribution and population densities are subject to strong fluctuations. In the Russian breeding areas and in Japan, the population of the species has been decreasing continuously over the past thirty years, but on the Korean Peninsula and in some places in China, the tiger shrike seems to be more common, at least regionally. The causes of inventory fluctuations or inventory decreases are not known. The IUCN estimates the population development as decreasing ( decreasing ), but does not list the species in any endangerment level.
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 .
- Norbert Lefranc, Tim Worfolk: Shrikes. A Guide to the Shrikes of the World. Pica Press, 1997, ISBN 1-4081-3505-1 .
- R. Yosef, E. de Juana: Tiger Shrike (Lanius tigrinus). 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 ( online , accessed 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
- ↑ EN Panov: The True Shrikes (Laniidae) […]. 2011, p. 624.
- ↑ a b c d R. Yosef, E. de Juana: Long-tailed Shrike (Lanius schach). 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 ( online , accessed November 25, 2014).
- ↑ a b Lanius tigrinus in the IUCN Red List of Threatened Species 2014.3. Listed by: BirdLife International, 2012. Retrieved November 16, 2014.
- ^ T. Harris, K. Franklin: Shrikes & Bush-Shrikes [...]. 2000, p. 193.
- ^ A b T. Harris, K. Franklin: Shrikes & Bush-Shrikes [...]. 2000, p. 195.
- ^ T. Harris, K. Franklin: Shrikes & Bush-Shrikes [...]. 2000, pp. 193-194.
- ^ T. Harris, K. Franklin: Shrikes & Bush-Shrikes [...]. 2000, p. 187.
- ↑ a b c d e f g T. Harris, K. Franklin: Shrikes & Bush-Shrikes […]. 2000, p. 194.
- ↑ a b EN Panov: The True Shrikes (Laniidae) […]. 2011, p. 633.
- ↑ xeno-canto: Sound recordings - Tiger shrike ( Lanius tigrinus )
- ↑ Norbert Lefranc, Tim Worfolk: Shrikes. A Guide to the Shrikes […]. P. 83.
- ↑ EN Panov: The True Shrikes (Laniidae) […]. 2011, pp. 624-625.
- ↑ a b EN Panov: The True Shrikes (Laniidae) […]. 2011, p. 626.
- ↑ EN Panov: The True Shrikes (Laniidae) […]. 2011, p. 627.
- ↑ EN Panov: The True Shrikes (Laniidae) […]. 2011, p. 634.
- ↑ a b c EN Panov: The True Shrikes (Laniidae) […]. 2011, p. 629.
- ↑ a b EN Panov: The True Shrikes (Laniidae) […]. 2011, p. 631.
- ↑ Wei Zhang, Fu-Min Lei, Gang Liang, Zuo-Hua Yin, Hong-Feng Zhao, Hong-Jian Wang, Anton Krištín: Taxonomic Status of Eight Asian Shrike Species (Lanius): Phylogenetic Analysis Based on Cyt b and CoI Gene Sequences . In: Acta Ornithologica . tape 42 , no. 2 , December 2007, p. 173-180 , doi : 10.3161 / 068.042.0212 .
