Red-shouldered shrike
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Red-shouldered Shrike ( Lanius vittatus ), male |
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| Valenciennes , 1826 |
The red-shouldered shrike ( Lanius vittatus ) is a songbird from the genus of the real shrike ( Lanius ) within the family of the shrike (Laniidae). The medium-sized strangler species is widespread from southeastern Iran eastward over most of India to around the lower reaches of the Ganges . Further east, separated spatially by the mouth of the Ganges and Brahmaputra , is the area of distribution of the Burmese strangler , which is regarded as the sister species of the red-shouldered shrike.
Like many other shrike species, the species feeds primarily on insects and other invertebrates . Occasionally, vertebrates such as young mice, nestlings and lizards are also preyed on. Most red-shouldered shrike remain in the breeding area all year round. Only the north-westerly populations are obligatory migratory birds with wintering areas on the macro coast or in northern India. A distinction is made between two subspecies, none of which are currently listed in a hazard level of the IUCN .
Appearance
The bay-backed shrike is 19 centimeters body length slightly larger than the similar in males backed Shrike , he is but leaner than this and so much more easily with an average of 20.8 grams. The male in particular is conspicuously colored with black, gray, rust-red and white plumage colors that contrast strongly in the fresh dress. There is no gender dimorphism in terms of height and weight, in terms of coloration it is very low. In some females, the black headband is a bit narrower and they are overall a bit paler, less contrasting in color. The latter characteristic is particularly evident in the subspecies L. v. to watch nargianus .
The typical black face mask covers the forehead and runs laterally over the eyes and cheeks to the neck. The rest of the head is gray, the throat whitish. Sometimes the face mask has a fine white border towards the crown. The gray color of the neck and upper back gradually merges into the rich chestnut brown of the back and coat. The rump is whitish-gray, the central feathers of the strongly tiered tail are black, the outer ones white. The wings are black, the hand wings in the basal section white, which creates a clear white wing surface when the bird is sitting and a distinctive, relatively wide, white wing field when flying. The belly is cream-colored, with a slight orange-red breath on the sides, the flanks usually more intensely colored light brown-reddish. The under tail-coverts are white. The mighty hooked bill is black, as are legs and toes.
Juveniles are gray-brown, clearly darkly banded on the vertex and neck, on the underside on a lighter background washed out banded and flocked. The face mask is indicated as a brownish cheek patch under the eyes. In immature red-shouldered shrike, the head and coat still have the banded appearance of juvenile, while the rest of the body plumage is already largely similar to the colored individuals.
After the breeding season, adults moult their entire plumage once a year. In most areas, moulting is complete by the end of August. It is not known whether this also applies to pulling red-shouldered shrimps.
In almost the entire range of the species there is also the chess shrike ( Lanius schach ), with which the red-shouldered shrike can be confused. The best distinguishing features are the much longer tail of the chess shrike and the lack of the white outer control feathers. In the extreme east of the distribution area there is a considerable possibility of confusion with the Burmese strangler. However, this has a reddish-brown rump and a slightly darker head color than the red-shouldered shrike.
Vocalizations
Both sexes are acoustically noticeable, especially in the pre-breeding season. The male's singing is a sustained, rather low warbling, chirping and whistling, sometimes melodic, but often interspersed with harsh, croaking or nasal-sounding elements. Sequences from other bird songs are usually inserted into this song. That of the female is similar, but mostly the phrases are shorter and quieter. The calls are screeching like jay.
Distribution, habitat and migrations
The distribution area of the red-shouldered shrike stretches from the macro coast in southeastern Iran and its hinterland through east and northeast Iran, Afghanistan , SE Turkmenistan , the extreme southwest of Tajikistan , almost all of Pakistan and India (except Assam ) eastwards to the mouth of the Ganges. In the northeast, the southern coverage of the Himalayan range in Nepal is reached. In this large area, the distribution is highly fragmented, in many places the species is completely absent or rather rare. The focus of the occurrence seems to be in northwestern and central India, the red-shouldered shrike is less common in the northeast (northern Pakistan, Turkmenistan) and in the far south ( Kerala and southern Tamil Nadu ). The habitat preferences of the red-shouldered shrike seem to lie between semi-deserts, which prefer the subspecies of the southern gray shrike ( Lanius meridionalis lahorta ) , which occurs sympatric in the northwest , and somewhat more densely wooded, relatively humid areas, which are preferred by chess shrike and Tibetan shrike ( Lanius tephronotus ).
In India, the red-shouldered shrike mainly inhabits dry grass-thorn bush land, interspersed with acacias and sections with very dense thickets. Occasionally it also breeds in rows of trees along irrigation canals, in border areas to cultivated land and on the edge of settlements, less often in parks and in large gardens. In the north-west, rocky regions with pistachio bushes are preferred, in the south-west Ziziphus and Prosopis populations. Vertically, the type is represented by coastal areas up to heights of about 2000 meters. Pulling red-shouldered shrike were observed at much greater heights.
The train movements have not been adequately researched. The northernmost populations are apparently obligatory migratory birds that leave the breeding grounds in late August / early September and return in late April / early May. You spend the winter mainly in India. Many birds from the more northerly areas of Iran, Afghanistan and Pakistan also migrate south, mainly to the coastal regions of the Arabian Sea . The departure times are a little later and the birds return to their breeding areas earlier. It is not known whether all the red-shouldered shrike move away from these breeding areas every year. Red-shouldered shrike have been observed in the United Arab Emirates , Oman , Saudi Arabia, and Bhutan .
Food and subsistence
Red-shouldered shrike and their young feed almost exclusively on insects, mainly beetles and grasshoppers . In terms of quantity, butterflies in their developmental stages, two-winged birds and hymenoptera such as bees and wasps are less important . Lizards , geckos , skinks , mice and nestlings make up occasional complementary foods that do not matter in terms of quantity.
The species hunts in the typical strangling manner from a raised hide about 2–2.5 meters high. From this a floor area of about 10 meters in a radius or semicircle is observed. If a prey is discovered, the shrike drops and hits it on the ground. Fleeing prey are pursued only briefly, if at all. Like many other species of shrike, the red-shouldered shrike creates food depots by impaling or pinching prey.
behavior
The red-shouldered shrike is diurnal like all other types of shrike. Panov describes it as a calm, balanced bird that often spends hours on the lookout for prey on a perch. Conspecifics are not tolerated in the territory, and the red-shouldered shrike also drives other strangles out of its territory if possible. The shortest distance between two flown nests was 150 meters in suboptimal habitats and around 50 meters in more favorable breeding areas. This type of strangler either flees from enemies in thick bushes or warns with loud shouts, especially against snakes or small owls such as the little owl . In front of people, she is remarkably tame and lets them get close. The courtship rituals consist of long series of calls from exposed waiting areas, showing spit places and potential nest locations, as well as conspicuous sightseeing flights over the territory. The most important poses when approaching a female are the upright sitting with the beak turned away from the female, deep, regular bows (nodding), as well as the hunched position, also used as a threatening gesture. In contrast to other, smaller species of shrike, female red-shouldered shrike are also very active and conspicuous during courtship.
Breeding biology
Red-shouldered shrike lead a largely monogamous seasonal partnership. There is no information about re-pairings of last year's breeding partners or about the continuation of the pair bond beyond the breeding season. The breeding seasons vary according to the extensive north-south range: in Turkmenistan the species breeds between May and July, in Pakistan between March and August, in northwest India from April to July and in the south of the subcontinent between February and April. In the northernmost breeding regions there is usually only one brood; a second brood only occurs when the brood begins very early or when the clutch is lost. In the rest of the distribution area, two annual broods are the rule, and occasionally three annual broods were found. The nest is a small, very compact bowl interwoven with blades of grass, stems, panicles and small twigs, lined with animal and plant wool and feathers on the inside and often camouflaged with materials from the nest environment and lichen on the outside. The average outside diameter is 10 centimeters and the inside diameter 6 centimeters; the depth of the bowl is about 4 centimeters. A number of low trees or bushes can be used as nest carriers, in the northeast of the distribution area there are almost exclusively pistachio bushes, otherwise thorny acacias or ziziphus trees are often chosen. The nest heights vary between 0.9 and 10 meters, but are mostly between 1.5 and 4 meters. The nest is built by both partners in about 5–8 days; If the clutch is lost, a new nest is built, often using materials from the old one.
The clutch consists of 3–5 (mostly 4) eggs of variable color and an average size of 20.8 × 15.7 millimeters. On a dirty-white, greenish-white, occasionally slightly pink background, they have brown, gray, and sometimes purple spots and spots, especially at the blunt end. They are laid every day and firmly incubated from the penultimate egg. It almost exclusively breeds by the female, only for very short periods - especially before sunrise and after sunset - is it replaced by the male. The young hatch after about 14 days within a few hours. During the nestling period, which also lasts around two weeks, the male largely procures the food for the young and partly for the female. In the case of the frequently occurring second broods, the male alone takes care of the cubs who are barely able to fly at first until they are completely independent after a further 8-10 days, and assists the female in building the new nest. The boys leave the parents' area at around 25 days of age.
Systematics
The exact relationship of the red-shouldered shrike within the genus Lanius has not yet been sufficiently clarified. It is likely that the Burmese strangler is a sister species. Whether the two species should be placed in the vicinity of Lanius collurio - Lanius phoenicuroides - Lanius isabellinus - Lanius cristatus - Lanius tigrinus - species group is questionable despite some similarities due to essential differences in terms of song and behavior. There are currently two well-differentiated subspecies:
- Lanius vittatus vittatus Valenciennes , 1826 : Central and southern part of the distribution area. Mostly stationary bird, short distance or partial migrant. Rich coloring, wide headband.
- Lanius vittatus nargianus Vaurie , 1955 : Southeast Turkmenistan, Southeast Iran, Afghanistan and Pakistan; to the southwest to the Indian Punjab . Mostly migratory birds. Much paler in color, narrow headband.
Existence and endangerment
No quantitative data are available, but the species seems to be frequent at least regionally with very different settlement densities. The largest settlement densities with 25-30 breeding pairs / km² were found in northern India, in southern Turkmenistan it is around 12-14 breeding pairs in good habitats, but mostly significantly less. The species is classified as harmless (LC = least concern ) by the IUCN .
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 , pp. 21, 56-57, 139-142.
- 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, International Shrike Working Group & E. de Juana: Bay-backed Shrike (Lanius vittatus). 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/60476 on November 4, 2014).
- Norbert Lefranc, Tim Worfolk: Shrikes A Guide to the Shrikes of the World. Pica Press, 1997, ISBN 1-4081-3505-1 .
- 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 Lanius vittatus in the IUCN Red List of Threatened Species 2014.2. Listed by: BirdLife International, 2012. Retrieved November 12, 2014.
- ^ A b T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 205.
- ^ Josep del Hoyo and others: Penduline-Tits to Shrikes. 2008, p. 780.
- ↑ a b c d e f g h T. Harris, K. Franklin: Shrikes & Bush-Shrikes ... 2000, p. 204.
- ↑ xeno-canto: Sound recordings - Bay-backed Shrike ( Lanius vittatus )
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 713.
- ^ Josep del Hoyo and others: Penduline-Tits to Shrikes. 2008, p. 781.
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 716.
- ↑ a b EN Panov: The True Shrikes (Laniidae) ... 2011, p. 728.
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 717.
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 727.
- ↑ a b c Yosef, R., International Shrike Working Group & de Juana, E. (2013). Bay-backed Shrike (Lanius vittatus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, DA & de Juana, E. (eds.) (2013). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/60476 on November 4, 2014)
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 724.
- ↑ a b EN Panov: The True Shrikes (Laniidae) ... 2011, p. 726.
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, pp. 724–727.
- ↑ EN Panov: The True Shrikes (Laniidae) ... 2011, p. 715.
