Black-fronted Shrike
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Black- fronted Shrike ( Lanius minor ) |
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| Lanius minor | ||||||||||||
| JF Gmelin , 1788 |
The lesser gray shrike ( Lanius minor ) is a species of the genus Lanius within the family of the Strangler (Laniidae). Black-fronted shrike are very similar to species from the group of the great gray shrike , but are somewhat smaller. The obligatory long-distance migrant with wintering areas in the steppe areas of the Kalahari is widespread from Eastern and Southeastern Europe eastwards to Central Asia. The species was still breeding birds in many areas of Western and Central Europe in the middle of the 20th century. Today it has become rare in these areas and has completely disappeared in many places.
features
With a total length of up to 20 centimeters, the black -fronted shrike is about the size of a starling , but significantly longer-tailed and slimmer than this. In the distribution of the gray, black and whitish plumage parts, it has very strong similarities with the northern and southern gray shrike , but can still be determined unequivocally if the observation conditions are sufficient.
The upper side plumage is unmarked gray from the vertex over the neck and back. The shoulders and the arm and hand wings are black. The rump is gray, as is the base of the clearly stepped tail, which is somewhat shorter than that of the predatory shrike. From the middle the tail is black, but the outer control feathers are white in the male. The underside is light. Breast and flanks are clearly exuded reddish brown, the belly is usually very light grayish brown. When the bird is sitting, the white bases of the hand wings create a very wide wing mirror that is always visible, and when it is in flight, a sickle-shaped white marking. The throat is almost pure white and contrasts very strongly with the wide black face mask that extends from the forehead over the eyes - which are broadly covered - to the neck. The black beak is clearly toothed, high and wide. The legs and toes are dark gray-brown. Occasionally there are very dark, melanistic individuals.
The sexes do not differ in size and weight. The differences in color, however, allow a reliable sex determination. Females are generally less contrasty in color, the black parts of the upper side plumage have an easily recognizable shade of brown. The outlines of the face mask in female black-fronted stranglers are clearly marked, but mostly not colored black, but mottled gray-black. In particular, the forehead is very rarely uniformly black, usually only gray-black flocked. Often a slight undulation and sparrowing of the gray upper side and light lower side plumage can be seen.
Soon after flying out, black-fronted shrikes molt into youthful clothes, which already show the drawing contours of the adult plumage. They are flocked gray-brown on top, the wings are black-brown. The large arm covers in particular have a clear, light border. The white wing mirror is already formed, and the eye mask is also indicated. The underside is light, washed out dirty white and isabel-colored on the flanks . Here a slight undulation and sparrowing of the plumage can be seen. In their winter quarters the young birds molt into adult plumage; Annual birds with remains of juvenile plumage are rarely found in the breeding area.
Possible confusion
The black-fronted shrike can be confused with the two types of the gray shrike, on the train also with the gray-coated shrike . It differs from all three species by its significantly smaller size, from the gray shrike by the wide face mask, which is never edged in white towards the top, and by the slimmer, far less bulky shape. The wing mirror is more pronounced and limited to the wings of the hand. Black-fronted shrike usually sit more upright than gray shrike. The gray-coat shrike can only be found in groups. He is noticeably long-tailed. In contrast to the black-fronted shrike, the tail is completely black in its second half. Young black-fronted shrike can only be clearly distinguished from juvenile gray shrike due to their smaller size.
voice
The singing is a typical, persistent chatter, in which, in addition to the croaking and pressed sounds characteristic of the species, many, sometimes very good imitations of other bird species and noises of the cultural landscape or barking dogs can be embedded (audio sample as video). Various bird species are imitated. The singing is usually preceded by a separate input element. The Reviergesang is a sustained modulated chirping that is performed in a slow flight of impressions.
Black-fronted stranglers also have a rich repertoire of calls. Most of them sound raspy and rough. Excitement calls are lined up reck… sreck sequences (audio example), or cheek-like chattering (audio sample), when predators appear loud gä… gägä sequences can be heard. An intimate, quiet contact call, made especially when building a nest, during courtship feeding or when handing over the food, is a quiet Krett .
distribution
The black-fronted shrike is widespread from eastern Central Europe east to the western border of Mongolia and into the border regions of northwestern China . The denser occurrences begin in Hungary , Slovakia and on the Balkan Peninsula , where around half of the total European population breeds in Romania alone, encompass large parts of Turkey , the Caucasus region in the southeast and extend into northern Iran . To the east they continued over the Ukraine and the north-eastern Black Sea region and extended far into the steppe belt of the Central Asian states . In northeastern Europe there are dwindling or very small breeding populations in Poland , Lithuania and Belarus , as well as strong populations in the European and Asian parts of Russia. The easternmost breeding areas are around 85 ° East, the northernmost at 55 ° North.
The previously not insignificant occurrences in the central and western part of Europe have largely been extinct apart from remains in northern Spain and southern France . In Italy , the distribution of the black-fronted shrike is highly fragmented.
The black-fronted shrike does not currently breed in Switzerland or Germany. In Austria there are occasional breeds of single pairs, especially in Seewinkel and in southern Styria .
Almost the entire world population spends the boreal winter in the Kalahari in southern Africa, especially in Botswana . According to Harris, the winter area is five times smaller than the breeding area, according to Herremans it is only a tenth. Only a few black-fronted shrike overwinter further north of this area, a few already in Iraq and in the south of the Arabian Peninsula .
hikes
All populations are long-distance migrants . Most European birds leave their breeding grounds in August and September, the first non-breeders as early as the end of July. They move in a corridor between the southwest and southeast mostly across the Balkans to the south, cross the Mediterranean on the Aegean island bridge and reach the African mainland in a relatively narrow area in the border area between Libya and Egypt . Most of them follow the Nile Valley further south . The breeding birds of Asia Minor migrate along the west coast of the Red Sea , the Central Asian ones cross the Persian Gulf and the southern part of the Arabian Peninsula and reach Africa in the area of the Horn of Africa . Black-fronted shrikes move at night. You will need between eight and ten weeks to move. They stay in the winter quarters for up to 22 weeks. The homecoming takes place on routes somewhat more easterly ( loop train ) and only takes six to eight weeks. The majority of the animals leave their winter quarters within a few days. The first black-fronted shrike reach the breeding grounds as early as mid-April, but the majority do not arrive until the beginning of May.
habitat
The black-fronted shrike often colonizes biotopes in its entire area of distribution, which are at least partially designed by humans and mostly, at least extensively, used. Of all Palearctic shrike species, it prefers the driest habitats, but does not breed in completely waterless regions. Important requisites for a suitable black-fronted shrike habitat are, in addition to sufficient food, stand-alone trees and open, short-grassed areas in which completely ungrown areas can be embedded. The type of trees doesn't seem to matter, but most of them are deciduous trees. Only in the high breeding areas of Central Asia does the species occur in old juniper stands. In contrast to most other species of shrike, the black-fronted shrike does not colonize tree-free regions consisting only of shrubs or bushes. In the pistachio savannah in southern Turkmenistan , it only occurs as a breeding bird when the pistachio grows like a tree. It inhabits loosened tree steppes up to the outermost edge areas of boreal forests as well as dry and mountain steppes, as long as there are enough trees available. Black-fronted shrike breed in extensive, ideally grazed orchards with large distances between the trees, in vineyards, in tree-lined pastures, often in avenues along road and railway embankments or in windbreaks made of poplar trees that border cultivated land. He avoids the proximity of humans less than the other European stranglers. Breeding sites in the immediate vicinity of inhabited houses are just as well known as those in parks in the middle of large cities. In Europe its breeding areas are below 900 meters, in parts of Central Asia and in the Caucasus it occurs as a breeding bird at heights of over 2000 meters.
In the boreal winter it is a character bird of the open acacia and thorn bush savannah. The black- fronted shrike prefers the drier habitats where the wintering areas overlap with those of the red killer . He lives in loosened mopane forests as well as cultivated land, where he often uses wires or the posts of cattle fences as waiting.
Like some other shrike species, black-fronted shrike tend to brood in a looser colony-like manner, so that there can be relatively high population densities in a relatively small area, but neighboring, equally well-suited habitats remain unused. For example, eight pairs successfully bred in an area of just 0.6 hectare near Odessa . However, such high settlement densities are the exception. Usually the nest spacing is between 50 and 300 meters.
Food and subsistence
The black-fronted shrike feeds almost exclusively on insects , especially on beetles living on the ground , which can make up over 90% of the total amount of food. It prefers larger species, but prey animals are picked up from a size of about 5 millimeters. Like other stranglers, it also eats species that protect themselves with stink glands or with a special warning system. In winter quarters, the desert beetle is one of its prey, which secretes a corrosive secretion. In addition to beetles, crickets and field and leaf locusts are often preyed on. Vertebrates, especially mice , shrews and birds, play only a very subordinate role; amphibians , various spiders , snails and worms are even more rare among the food animals. In extreme emergency situations, black- fronted shrikes can eat their own brood ( Kronism ). At least in the wintering area, the species has not yet been observed drinking.
Among the beetles predominate in all studies, ground beetles , well ahead of weevils , Aaskäfern and scarab beetles . Species that are particularly frequently eaten in the breeding area are grave beetles , for example Pterostichus vulgaris , the cockchafer , or grave digger species , but the species composition depends on the respective offer.
The predominant hunting method of the black- fronted shrike is high-seat hunting . The waiting areas are mostly 2–3 meters high. Higher bushes, side branches of trees, parked agricultural equipment, very often power lines, termite mounds in the wintering area and many other elevated positions offering a good overview can serve as waiting areas. When there is no waiting , black- fronted shrike keep shaking . The prey is usually beaten on the ground and consumed there, but larger prey animals are brought to a hide and prepared there for consumption, while they are held with one foot. Occasionally it catches prey such as cockchafer, rose beetle or bumblebee and other straight-flying insect species in the air.
Black-fronted shrike skewer food animals only extremely rarely; they do not store supplies in any other way either. The absence of these behaviors makes them particularly vulnerable to food shortages.
Territorial and antagonistic behavior
The territoriality and the associated aggressiveness is very different for this species. In the minimum case, the black-fronted shrike only defends the nest location itself and a small surrounding area. Conspecifics brooding in the vicinity are largely ignored. The food territories of the district neighbors can largely overlap without rivalries occurring. In the opposite case, however, the territories can be significantly more extensive, include several favorite control centers and be aggressively defended. The black-necked shrike can be extremely tolerant towards other bird species and other shrikes. Black-fronted shrike recognize the territories of neighboring, more aggressive shrike species very quickly and respect them. A brood aggregation of golden oriole , gray shrike , red-headed shrike and black- headed shrike was once observed without any notable disputes.
In the wintering areas, small groups of black-fronted stranglers can often be found together, often associated with other bird species such as red-footed falcons or field thrushes .
Antagonistic behaviors towards conspecifics are particularly common in the pre-breeding season and in the early breeding season. In most cases, showing off, flying towards you and loud shouts are enough to drive away an intruding conspecific. Chases can occur, but these rarely lead to contact fights.
Black-fronted shrikes warn of nest predators such as crows or various species of birds of prey with loud nagging. When approaching, they fly directly towards them and attack them until they touch. Several neighboring breeding pairs often participate in this defense. Escape behavior from people is very different from region to region and from person to person. In winter quarters, black-fronted shrike behave much more shyly than the red-backed shrike.
Breeding biology
Black-fronted shrikes reach sexual maturity at the end of their first year of life. As far as is known, they have a monogamous seasonal marriage. Since the females in particular show a low level of loyalty to the breeding site, re-breeding between last year's partners is likely to be rare. Black-fronted shrike only breed once a year. In the event of clutch loss or brood loss in the early nestling stage, a replacement clutch is created, almost always in a different breeding tree, often in a completely new area.
Courtship, nest building and nest
Black-fronted shrike often appear already paired in the breeding area, then the courtship takes place quite secretly. However, unmated males are very noticeable. In courtship flight the male flies slowly circling with very flat wing beats, often sailing, low over the territory. If a female comes, she soon sits down next to it, bows, switches from one side to the other. When bowing, it trembles its wings, its tail is spread apart. Occasionally it flies up and performs ritualized nesting trough movements in a forked branch. Very soon it also brings prey and passes them on to the female. This behaves quite passively for a certain time and often does not accept the presented food animals at the beginning. The pair formation is completed when both choose a nesting site together and start building the nest. At this point the first copulations take place.
Almost always trees are nest carriers, only in very rare exceptional cases also higher bushes. The tree species varies widely, but poplars seem to be preferred in some areas . The nest is a compact, firmly attached bowl that is made exclusively from fresh plant stems at heights between 4 and 12 (exceptionally 20) meters, often close to the trunk, but also in the forks of side branches, occasionally in old magpies or crow nests. Aromatic plants such as chamomile , sage or mugwort , or plants with white hairs are preferred when building nests. Woody material is not used. The inside of the bowl is lined with soft plant fibers, animal and plant wool, bird feathers and animal hair.
Clutch and brood
The clutch consists of 5–6 (3–9) eggs with an average size of 25 × 18 millimeters, which are spotted green-brown or olive-green on a blue-gray background at the blunt pole. Clutches are smaller and can only contain three eggs. The eggs are laid every day and incubated by the female only from the penultimate egg. During the breeding season and the early nestling period, the male provides the female with food, which occasionally leaves the nest to look for food. The young hatch after about 15 days. In larger clutches, the hatching process can take several days, so that there can be considerable developmental differences between the young. The chicks hatch naked; From the 8th day the feathers begin to open, on the 11th day they are largely completely feathered. In the first few days they are hoofed by the female and fed with the food brought in by the male; later the female takes part in the foraging. Depending on the weather, the young leave the nest after about 16 days, but remain in the nesting tree for at least one more day. The parents look after the boys for at least two weeks, sometimes in two separate management groups.
Breeding success and life expectancy
There are only a few studies on the breeding success of the black-fronted shrike. In general, there is a very strong dependence of the breeding success on the weather during the breeding season. In Rhineland-Palatinate in the early 1960s, 33.5 percent of 147 controlled clutches were lost by the age of ringing of the boys due to predation or weather influences. This percentage, which is not unfavorable for stranglers, rose to 59–75 percent in the cold, wet summers of 1965–1967. In general, the black-necked shrike seems to be able to achieve better breeding success than the red-headed shrike under favorable weather conditions. In addition to weather influences, disturbances at the breeding site and predation by small mammals, crows and owls, in Central Asia also by snakes, lead to breeding failures.
No data are available on life expectancy.
Systematics
The black-fronted shrike is one of at least 26 species of the genus Lanius . Their representatives are widespread in Africa, Europe and Asia. In North America only two species occur, in South America and Australia no species of this genus breed. Within this genus, the black-headed shrike is probably most closely related to the long-tailed shrike and the red-headed shrike , which are native to Africa south of the rainforest belt . In rare cases, the black-fronted shrike hybridizes with other shrike species. Two cases of mixed broods with the red- backed shrike and courtship behavior towards the red-shouldered shrike were observed.
Mostly the slightly larger and lighter subspecies L. minor turanicus is distinguished from the nominate form occurring in the western part of the distribution area to western Russia , but this subspecies is not generally recognized.
Inventory and inventory development
The IUCN does not list the black-necked shrike in any risk level. BirdLife Europe assesses the population situation of the species as slightly declining . Population increases in Bulgaria and Russia contrast with decreases in the other European breeding areas. The main focus of distribution in Europe is in Romania, where BirdLife Europe suspects up to 857,000 breeding pairs, a number which, according to Harris, who gives only 70,000, is likely to be too high. There are no population estimates for the non-European breeding occurrences.
Since the species overwinters in a relatively small, unfragmented area, the total world population of around 6 million individuals can be extrapolated relatively precisely by censuses in this area.
The population of the black-fronted shrike is generally subject to great fluctuations, which are primarily associated with unfavorable weather conditions during the breeding season. These stock fluctuations have a particularly serious effect in the peripheral zones of the distribution area. After an almost complete collapse at the beginning of the twentieth century, stocks in Central Europe recovered around the middle of the century. Towards the end of the 1950s, more than 1000 pairs were breeding in Germany, around 500 in Austria and there were still quite strong breeding incidence in Switzerland. After that, a rapid decline set in, which on the one hand can be linked to the cold and wet summers of the late 1960s, and on the other hand is due to the intensification of pesticide input and habitat destruction in the breeding areas. The species has not yet recovered from this collapse in populations in large parts of the central and north-eastern European peripheral zones. In addition, direct tracking, especially on the train, has the effect of minimizing the population, while insect control in the wintering areas is likely to play only a very minor role.
literature
- Hans-Günther Bauer and Peter Berthold : The breeding birds of Central Europe. Existence and endangerment. Aula, Wiesbaden 1997, ISBN 3-89104-613-8 , pp. 434f.
- Javier Gonzales, Michael Wink, Eduardo Garcia-del-Rey and Guillermo Delgado Castro: Evidence from DNA nucleotide sequences and ISSR profiles indicates paraphyly in subspecies of the Southern Gray Shrike (Lanius meridionalis) . In: J. Ornithol. (2008) 149: pp. 495-506.
- Urs N. Glutz von Blotzheim (Hrsg.): Handbook of the birds of Central Europe. Edited by Kurt M. Bauer and Urs N. Glutz von Blotzheim, among others. Aula-Verlag, Wiesbaden 1985 ff. (2nd edition). Partial volume 13/2, ISBN 3-89104-535-2 , pp. 1229-1261.
- Tony Harris, Kim Franklin: Shrikes & Bush-Shrikes . Helm identification Guides, London 2000: pp. 163-167; Plate 5, ISBN 0-7136-3861-3
- Marc Herremans: Monitoring the world population of the Lesser Gray Shrike (Lanius minor) on the non-breeding grounds in southern Africa . In: J. Ornithol. 139. 1998, 485-493.
- Evgenij N. Panow: The stranglers of the Palearctic. (= Die Neue Brehm-Bücherei. Volume 557). Westarp-Wissenschaften, Magdeburg 1996, ISBN 3-89432-495-3 , pp. 148-171.
Web links
- Good pictures
- Black-fronted shrike feathers
- Videos, photos and sound recordings on Lanius minor in the Internet Bird Collection
- Age and gender characteristics (PDF; 0.7 MB) by Javier Blasco-Zumeta and Gerd-Michael Heinze (English)
Individual evidence
- ↑ a b Harris (2000) p. 163
- ↑ HBV Vol. 13/2 (1993) p. 1235
- ↑ ( page no longer available , search in web archives: audio sample )
- ↑ a b HBV Vol. 13/2 (1993) p. 1237
- ↑ Call1 (WAV) birdsongs.it. Retrieved October 25, 2019.
- ↑ Call2 (Wav) birdsongs.it. Retrieved October 25, 2019.
- ↑ a b c data sheet Birdlife Europe engl.
- ↑ a b c d e Harris (2000) p. 164
- ↑ a b Herremans (1998) p. 488
- ↑ a b Harris (2000) p. 165
- ↑ Panow (1996) p. 131
- ↑ a b c Panow (1996) p. 149
- ↑ HBV Vol. 13/2 (1993) p. 1251
- ↑ a b HBV Vol. 13/2 (1993) p. 1252
- ↑ a b Harris (2000) p. 166
- ↑ HBV Vol. 13/2 (1993) p. 1258
- ↑ HBV Vol. 13/2 (1993) pp. 1253-1254
- ↑ Harris (2000) p. 167
- ↑ a b Panow (1996) p. 169
- ↑ a b HBV Vol. 13/2 (1993) p. 1256
- ↑ Gonzales et al. (2008)
- ↑ Lanius minor in the Red List of Threatened Species of the IUCN 2011.2. Listed by: BirdLife International, 2009. Retrieved November 13, 2011.
- ^ Bauer & Berthold (1997) p. 434
- ↑ Herremans (1998) p. 491