Red-footed falcon
| Red-footed falcon | ||||||||||||
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Red-footed falcon, male |
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| Falco Vespertinus | ||||||||||||
| Linnaeus , 1766 |
The red-footed falcon ( Falco vespertinus ) is a small representative of the real falcon within the family of falcon-like (Falconidae). In the dark blue-gray males, the rust-red fletching of the red legs is particularly noticeable. In females, the dark upper plumage contrasts with the orange-brown head and lower plumage. The closed distribution area of the species extends from Hungary eastwards to the Baikal area . Since the 1960s, the numbers of the red-footed falcon have been declining in almost the entire range of the species.
description
The upper side of adult males is dark blue-gray. Usually this shade of gray is a little darker in the head area, especially around the eyes. The arm and hand wings are lighter silvery-gray on the upper side, which creates a striking contrast to the dark upper wing ceilings. The underside of the bird is also slate gray with the exception of the lower abdomen, the lower tail-coverts and the fletching of the legs ("pants"), which are deeply reddish brown in color. Also striking are the iron oxide red eye ring and the equally colored wax skin . The beak is blue-gray and darkens towards the tip, the claws are very light, only their tips are dark gray. The legs and toes are salmon red.
Adult females are very different from males. Their upper side is lighter slate gray, often also slightly brown gray with distinct, dark gray banding. The tail is slightly lighter than the upper plumage and has some dark bands. The subterminal tape (compare the end band ) is almost black and slightly wider, the tips of the control springs are dirty white or cream-colored. The neck, the upper part of the head and the entire underside are bright brownish-orange. The abdominal plumage shows indistinct, black longitudinal lines. The cheeks and throat are white. The black eye mask, which extends into a short strip of beard towards the cheeks, is striking. The eye ring and the wax skin are bright orange. Legs and toes are deeply orange, the claws light (yellow) with a dark tip. Juvenile red-footed falcons are not always easy to identify using field ornithology. Its top is matt dark brown and looks a bit scaly. The wing feathers are dark, but do not contrast very clearly with the rest of the upper plumage. The underside is light, the color varies between pale orange and pale brown, the arm and hand wings are gray-brown with clear light stripes, as in adult females. The tail is clearly banded and has a broad, dark subterminal band. The head and vertex are light brown or brownish-orange and clearly delicately dashed. The eye mask and beard are brown, wax skin and dark circles are yellow-orange. The legs and toes are pale yellow.
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Immature red-footed falcons (individuals that have not yet been colored) are usually easy to identify even in the wild, as the characteristics of the adult dress are already well developed in them, albeit very different from each other. When viewed from below, they often give an inconsistent, piebald impression, as the chest and abdominal plumage, the under wing coverts and some (mostly the inner) hand wings have already blossomed into adult clothing, while the other hand wings and most of the arm wings still have the gray-brown, white speckled color of the youth dress. In the upper view, an immaturer is already largely like an adult red-footed falcon, only the outer control feathers have clear white marks. Often an orange-brown, usually not closed, neck ring can also be seen. At the end of the second year of life, red-footed falcons change into adult clothes.
The agile, fast and agile flight of the red-footed falcon is regularly interrupted by short gliding phases in which the wings are stretched backwards in a sickle shape. The species shakes frequently, mostly close to the ground and not as persistent as the kestrel . The body position is more horizontal than that of kestrels. In soaring flight the stretched wings are slightly lowered, the tail is broadly diversified.
Dimensions and body mass
The body length is between 29 and 31 centimeters. The span varies between 60 and 75 centimeters. The size of the red- footed falcon is roughly the same as that of the red- footed falcon and, with the same wingspan, is slightly smaller than a kestrel and significantly smaller than a tree falcon . Males weigh between 115 and 190 grams, females are slightly heavier at 130 to 197 grams. Overall, however, the sex dimorphism in terms of size and weight is small compared to other birds of prey.
voice
As colony breeders, red-footed falcons are very vocal. They are particularly loud in the pre-breeding season and in resting groups. In contrast, single brooding pairs are not very noticeable acoustically. The calls are similar to those of the tree hawk, but they are higher, softer and slower. With increasing excitement, the calls become more acute and the intervals between the individual elements shorter. They can be roughly transcribed with kjiiie-kjiie . They are distantly reminiscent of the shouts of the turning neck . The female's calls are similar but sound a little pathetic. When excited, they vibrate strangely and then sound cheeky. Often a long drawn is Lahnen that as thschree - triiie - triii sounds to hear.
Possible confusion
Especially juvenile red-footed falcons can easily be confused with young tree falcons. In the juvenile tree falcon, the head and the face mask are dark, almost black, the wax skin and the dark circles are inconspicuous blue-gray. The middle tail feathers of the tree hawk are solid dark gray and have no banding. In the flight image , the larger wingspan of the tree falcon, the wider wings at the base and the more powerful, clumsier-looking flight are striking. Even Merlin females are very similar juvenile Red-footed Falcon, but allow much lower span of Merlin, his overall rather triangular wing outline and the completely different way of flying usually a reliable determination.
Systematics
F. vespertinus is close to the Amurfalken ( Falco amurensis ) is used, the distribution area to the east connects the Red-footed Falcon, and up to the Amur , southeast to North Korea ranges. This species is slightly smaller than the red-footed falcon and differs significantly from it, especially in the plumage of the females. Female Amur falcons have a dark slate-gray head. The dark circles and wax skin are brick red. The underside of the females shows a distinct black spot on a pale brownish orange background. Amur falcons fly to the same winter quarters as red-footed falcons. This species is occasionally found on the homeward journey in southern Europe. Until a few years ago, the Amur falcon was considered a subspecies of the red-footed falcon ( Falco vespertinus amuriensis ), but is now regarded as an independent species, so that no subspecies of the red-footed falcon are described.
distribution
The main areas of European distribution are in southern Russia and Ukraine . The species occurs in larger numbers in Hungary , Romania and Serbia . Smaller populations exist in Italy , Bulgaria and Moldova , in Austria , Slovakia , and in Belarus . The red-footed falcon also breeds irregularly in the Czech Republic and the Baltic States , and occasionally in Germany . In Asia, the breeding occurrences run in a relatively narrow band a little south of the closed taiga eastwards to the upper Lena , where they touch the distribution area of the sister species Falco amurensis east of the Baikal . The northern limit fluctuates between 63 ° and 58 ° north latitude, the southern limit around 45 ° north latitude. It initially runs along the northern canopy of the Altai and then follows the transition from loosened pine forests to the treeless steppe areas of Central Asia to the west. Further west, the closed breeding areas on the lower reaches of the Volga and on the north coast of the Caspian Sea reach Europe. The southernmost occurrences are in the steppe areas north of the Caucasus and in South Georgia . Some island-like breeding areas can be found in northern Turkey . They spend the winter in southern and eastern Africa.
habitat
The red-footed falcon is a resident of largely open landscapes with groups of trees or interspersed with small forests. In addition to an abundant supply of large insects and small mammals, the species is dependent on the availability of suitable nesting facilities, especially old rooks and magpies' nests . In its key distribution areas in Central Asia and Southeast Europe, it occurs mainly in tree-steppe areas. However, it also inhabits the southern edge of the closed Palearctic belt of coniferous forests, particularly those regions in which the closed spruce stand merges into a loosened pine stand. The species is also able to penetrate large, contiguous forest areas if large clearings have been created there by storms, fires or clear cuts. In its northern distribution areas, red-footed falcons breed in tree-lined heathland as well as in bog areas . Likewise, loosened alluvial forests and , more rarely, cultivated land bounded by rows of trees can be breeding habitats for the red-footed falcon. Wherever there is sufficient tolerance by humans, red-footed falcons can nest near or on the outskirts of settlements. Desert areas are never populated, treeless steppe areas only in exceptional cases, especially if there are breeding opportunities on cliffs or rocky islands. The red-footed falcon is an inhabitant of the lowlands. In Europe there are only a few breeding sites above 300 meters above sea level. In Asia, the species occurs up to 1500 meters above sea level .
In winter quarters, where the nature leads a nomadic life, various types of landscape as are wet savannah , dry savannah , thorn grass savannas , and open grassland consulted.
Food and subsistence
The food source of adult red-footed falcons consists almost exclusively of large insects and a few other invertebrates . However, the young are mostly fed with reptiles , amphibians and small mammals . A particular preference for individual species cannot be determined. In the stomachs of examined red-footed falcons, such species were found in abundance, which occur seasonally frequently and are easy to hunt. In terms of quantity and weight, relatively large species such as grasshoppers predominate , including crickets , as well as beetles, especially cockchafer , dung beetle ( e.g. Geotrupes sylvaticus ) and ground beetles , dragonflies and butterflies (both larvae and imagines ). In addition, various hymenoptera such as bees , wasps and two-winged birds play a certain role in the food spectrum of this species. If there is a particular food shortage, other invertebrates such as spiders , snails and earthworms are also eaten. In early spring, when large insects are not yet available in sufficient quantities, and while rearing young, the red-footed falcon beats small rodents up to the size of hamsters and young ground squirrels , as well as shrews . Small birds and nestlings, reptiles and amphibians are also important food components during this time. With gradations of certain prey, e.g. B. the field mouse ( Microtus arvalis ), or the common garlic toad ( Pelobates fuscus ), these can become almost exclusive prey.
In winter quarters, locusts, cicadas , termites and winged ants are the main sources of food.
Red-footed falcons are both high seat hunters and search aircraft hunters. In the hide hunt, they observe the surroundings from a mostly low-lying control room and capture their prey either in the air or on the ground in short flights out. In the search flight, smaller sections of the terrain are searched for in a slow flight, interrupted by shaking phases. This flight changes constantly in height and is somewhat reminiscent of the hunting flight of the black tern ( Chlidonias niger ). The prey is seized with outstretched fangs. Smaller prey animals are eaten in flight after biting off the head, larger prey are carried to a hide and cranked there . Often red-footed falcons hunt on foot, where they move very skillfully hopping and walking. The hunt is often done in small groups. It is not known whether coordinated hunting methods take place in these. Occasionally, red-footed falcons hunt other smaller falcons, especially red- hawk falcons ( Falco naumanni ), for their prey.
behavior
If the food supply and the availability of breeding opportunities permit, red-footed falcons live socially, with group sizes varying between several pairs and several hundred pairs. However, colonies with more than 20 breeding pairs have become rare in Europe. At the edges of its range in the west and north, the species usually breeds individually. Red-footed falcons do not claim any territory. Even within the breeding colony in which the cavity spacing old by the continued use Rabenvogel -Nester are given, the way towards the breeding neighbors is very friendly. Alien intruders, especially crows, are vigorously driven away by the breeding partners who are most exposed to the aggression. Other colony members participate by shouting loudly, but not actively in the dispute. Even outside the breeding season, red-footed falcons are rarely found individually. They gather in large train communities and also spend the time in their winter quarters in large groups. Hunting and sleeping societies with more than 1000 individuals were observed.
As with the red hawk, the activity profile of the species is two-pinned. The first intensive hunting phase, which begins later in the morning, is followed by an extensive rest and cleaning interval that lasts until around 4 p.m. in summer. During this time the colony members rest or are busy with feathers care. Even very easily accessible prey is usually ignored during these hours. Only when food is scarce and during the breeding season can the first prey flights begin in the early morning hours. The second activity peak extends from late afternoon to late twilight, and on bright moonlit nights until late at night. Even during the breeding season, the day ends with group, loud flying games.
Courtship and pairing
Red-footed falcons reach sexual maturity at the end of their first year of life, but many do not breed until the following year. You lead a monogamous breeding season marriage. It is not known whether pairs appear mated in the breeding area. Main courtship and pair formation only take place in the breeding area. The main elements of the relatively short courtship are the male's sightseeing flights, which are very similar to those of the kestrel. The male rises and flies around the sitting female, turning and twisting, on which it repeatedly pushes down and occasionally even touches it. The female crouches, slightly ruffles her back plumage and straightens her tail. These flying games are accompanied by loud calls from both partners. Occasionally the male lands next to the female and hands over prey. The recurring ceremonial nesting is also an element of courtship, which primarily has the function of coordinating the choice of nesting place of the partners, who often have different nests in mind. The copulations take place on the nest or on a branch and are carried out in ever shorter intervals towards the egg-laying.
Clutch and brood
Immediately after arriving in the breeding area - depending on the region from the end of April to the end of May - the returning falcons try to occupy nesting sites. Usually old, no longer used crow's nests are used. Magpie, carrion crows , and especially rooks, are the most common nest suppliers. Occasionally, clumps of birds of prey are also used. Since the rook only breeds in colonies, social breeding is practically given to the red-footed falcon. If rook nests are used, the higher ones seem to be more attractive than those lower in the wood. Usually the occupied nests are not occupied. Occasionally, red-footed falcons wait to lay their own eggs until the previous owner's nestlings have flown out. However, it was also observed that pairs of red-footed hawks attacked breeding rooks and hooded crows and driven them away from the nest. Breeding rarely occurs on cliffs or in semi-caves. Occasionally, ground broods have also been found.
The clutch consists of three to four, dense reddish-brown speckled, rather blunt-oval eggs with average dimensions of 37 × 29 millimeters on a light background. The egg weight averages 21 grams. The eggs are similar in size and appearance to those of the kestrel, but are slightly smaller and slightly lighter. Large clutches with six eggs were found as well as those with only one egg. It is unknown whether additional clutches occur when the clutch is lost. Egg-laying begins two to three weeks after arrival in the breeding area, in south-eastern Central Europe around mid-May. The latest arrival dates come from northeastern Siberia, where the stocks do not arrive until the second decade of June.
The clutch is usually incubated by both partners after the second egg has been deposited. The male also develops a brood spot during this time . The exact incubation period is not clear. Older data of only 22-25 days are now mostly classified as too short exceptional observations. The average incubation period is likely to be 27–28 days. Only a few data are available on the nestling duration, most authors give it as 26–28 days. In the first two weeks, the chicks are fidgeted and shaded by the female , who breaks up the food brought by the male. Then the female also takes part in the foraging for food. After flying out, the young become independent very quickly and can catch prey after two weeks. The family association then dissolves.
hikes
Red-footed falcons are obligatory long-distance migrants , which means that they always make the move regardless of climatic events. All populations spend the Palearctic winter in the southeast and South African winter quarters. The birds of the East Asian breeding areas also migrate to these areas, covering distances of well over 20,000 kilometers. Wintering in the Crimea , Macedonia and Turkey was very rare . Before the flight from the end of August to mid-September, extensive train companies gather in the breeding areas. The species mostly migrates during the day and at great heights, often together with other smaller falcons. The eastern populations first fly west and swing south in the area of the eastern shore of the Black Sea and the eastern Mediterranean. Sometimes this initial westerly migration takes place further north, so that autumnal influx of red-footed falcons into southern Sweden and northern Germany occurs. The Eastern European breeding birds immediately move in southeast directions. They reach their wintering areas in Angola , Zambia , Namibia , Botswana , Zimbabwe and the Republic of South Africa around mid-November and stay there until the end of February. The homeward journey runs much further west, so that the Mediterranean is often flown over in its western and central areas in a broad front ( loop train ). Special weather conditions lead the species regularly on its way home to Central Europe, occasionally to northern Germany, Great Britain and the Netherlands. In 1992, over 1500 migrating red-footed falcons were counted in the Netherlands.
Persistence and Threat
As with other large insect hunters, the red-footed falcon population has been negative since the 1960s, and in some regions such as Hungary even strongly negative. In 1998, more than 2000 pairs were breeding in Hungary; in 2002, the population was estimated at a maximum of 1000 breeding pairs. The fact that large breeding colonies have largely disappeared, but productivity in such colonies is significantly greater than in smaller colonies or with individual breeders, proves particularly negative. This development gives rise to fear of a further decline in stocks in the near future. In addition to the destruction of biotopes and direct tracking, the large-scale use of biocides in particular has a negative impact on the population. Today they seem to suffer mainly from the control of locusts in the wintering areas. The pursuit of rooks and magpies, the most important eyrie suppliers, also reduced the occurrence of the species.
More recent studies assume about 32,000 breeding pairs in Europe, Ferguson-Lees and Christie put the world population at at least 100,000 breeding pairs. Since many areas of Asia with suitable biotopes have not been ornithologically examined, the actual world population could be significantly higher. According to the IUCN , the red-footed falcon is considered near threatened , so it is just about to be endangered. Birdlife Europe classifies the stocks as vulnerable (endangered) - mainly because of the significant declines in Ukraine and the European part of Russia , but the recently extrapolated total Ukrainian stocks are not included in this assessment.
However, positive developments can also be recorded. In eastern Austria and western Slovakia, where the species stopped breeding towards the end of the 1980s, the red-footed falcon is once again a regular breeding bird. In 1995 the first broods in Italy were found in the Parma area . Today up to 70 pairs breed, especially in the province of Ferrara .
Name derivation
The habit of the red-footed falcon to hunt until late at night is borne out by the scientific name: Latin vespertinus can be translated as evening . Also in Danish ( Aftenfalk ) and in Swedish ( Aftonfalk ) this property gave the name. In Italian the species is called Falco cuculo , which indicates a certain similarity between juvenile red-footed falcons and a cuckoo ( Cuculus canorus ). In many other languages, the conspicuous red legs of the males of this species are responsible for the name, such as Cernícalo de patas rojas in Spanish, which translated means falcon with red legs .
literature
- Hans-Günther Bauer and Peter Berthold : The breeding birds of Central Europe. Existence and endangerment. Wiesbaden 1998, ISBN 3-89104-613-8 , p. 122f.
- Mark Beaman and Steven Madge: Handbook of Bird Identification. Europe and Western Palearctic. Stuttgart 1998, pp. 207 and 246, ISBN 3-8001-3471-3
- James Ferguson-Lees and David A. Christie: Raptors of the World . Boston / New York 2001, pp. 864-867; Plate 99 (p. 276), ISBN 0-618-12762-3
- Benny Génsbøl and Walther Thiede: Birds of Prey. All European species, identifiers, flight images, biology, distribution, endangerment, population development. Munich 2005, ISBN 3-405-16641-1
- Urs N. Glutz von Blotzheim , Einhard Bezzel and Kurt M. Bauer: Handbook of the birds of Central Europe . Volume 4, 2nd edition, Wiesbaden 1989, ISBN 3-89104-460-7 , pages 768-788.
- Theodor Mebs and Daniel Schmidt: The birds of prey in Europe, North Africa and the Middle East. Biology, characteristics, stocks. Stuttgart 2006, pp. 382-388, ISBN 3-440-09585-1
- Viktor Wember: The names of the birds of Europe. Meaning of the German and scientific names. Wiebelsheim 2005, pages 66, ISBN 3-89104-678-2
swell
- ↑ Handbook of the Birds of Central Europe (HBV) Volume 4, 1988, p. 787.
- ↑ HBV (1989) p. 786f.
- ↑ HBV (1989) p. 783.
- ↑ Ferguson-Lees and Christie (2001), p. 867; Mebs and Schmidt (2006), p. 387.
- ↑ Mebs and Schmidt (2006), p. 387.
- ↑ Mebs and Schmidt (2006), p. 387; Ferguson-Lees and Christie (2001), p. 865.
- ↑ a b Mebs and Schmidt (2006), p. 384.
- ↑ Ferguson-Lees and Christie (2001), p. 867.
- ↑ Factsheet Birdlife Europe
Web links
- Information about the red-footed falcon
- Falco vespertinus in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 31 of 2009.
- Videos, photos and sound recordings on Falco vespertinus in the Internet Bird Collection
- Feathers of the red-footed hawk
