Bonelli's eagle (species)
| Bonelli's eagle | ||||||||||||
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Bonelli's eagle ( Hieraaetus fasciatus ), adult |
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| Hieraetus fasciatus | ||||||||||||
| ( Vieillot , 1822) |
The Bonelli's eagle ( Hieraaetus fasciatus , syn .: Aquila fasciata ) is a species of bird from the family of the hawk-like (Accipitridae). This medium-sized, powerful and very agile eagle inhabits dry, rocky regions in southern Europe, North Africa and southern Asia, where it feeds on small to medium-sized vertebrates . The population of the Bonelli's eagle in southern Europe has been declining for decades, mainly due to illegal persecution, which is why the species is considered to be endangered here.
description
Bonelli's eagles are medium-sized, strongly built eagles and are significantly larger and heavier than a common buzzard . The body length is 55–67 cm, of which 24–29 cm is accounted for by the tail. The wingspan is 142–175 cm. Females are on average around 10% larger than males, the sexes do not otherwise differ externally. Females of the nominate form have a wing length of 478-560 mm, males reach 458-542 mm. Up to now hardly any information on the weight is available, two females weighed 2.0–2.5 kg, four males 1.5–2.2 kg. The legs are relatively long and, like all members of the subfamily Aquilinae, feathered down to the toes, the toes and claws are very large and strong.
In flight, the species appears broad-winged, with clearly, but not as strong as in the large species of the genus Aquila fingered wings and slightly S-shaped rear edge of the wings. The thrust is long and straight at the end.
In adult birds, the top of the trunk and wings as well as the top of the head are a single color, dark black-brown, with a whitish spot in the middle of the back. The tail is gray and shows fine, dark banding and a wide, dark subterminal band. The underside of the fuselage as well as the small under wing coverts are dotted with black dots of variable thickness on a white background and thus form a clear contrast to the monochrome black middle and large under wing coverts. The arm-wings and the inner hand-wings are also monochrome dark brown-gray underneath, the outer hand-wings are banded dark on a whitish background.
The iris is pale yellow to amber , the wax skin and toes are yellow in color. The base of the beak is gray compared to the otherwise black beak.
The youth dress differs significantly from that of the adult birds in terms of color and drawing. The upper sides of the wings and fuselage are warm brown in a single color, a light spot on the back is missing. The underside is faintly dark dashed on a yellowish-ocher-colored background. All rockers and control springs show a narrow, dark band on a light gray background. The irises of the young birds are warm brown, the wax skin and toes are yellow, as in adult birds. After the first moult, juveniles show a mixture of juvenile and adult plumage; after the second moult, i.e. in the autumn of the third calendar year, they are colored and can no longer be distinguished from adult birds.
Vocalizations
During courtship, a loud, shrill call is often uttered, which is described as "hiiiiiü-hiiiiü" or "jiöh". When the nest is threatened or other agitation, Bonelli's eagles line up and whistle high and shout “ki-ki-ki” or “jib-jib-jib”.
distribution and habitat
The Bonelli's eagle occurs in southern Europe , North Africa, on the Arabian Peninsula as well as in South and Southeast Asia , although the distribution is highly fragmented. The largest contiguous distribution areas are in south-western Europe in Spain , Portugal and in the south of France and then to the south in north-western Africa, then on the Indian subcontinent and in southern China . In Europe there are also smaller breeding populations in Sardinia , in the extreme south of Italy , in the Balkans as well as in Greece and Cyprus .
In the western and central part of its range, the Bonelli's eagle mainly inhabits the Mediterranean and arid climatic zones. It occurs there mainly in dry, mountainous areas with rock faces and little forest cover. Outside the breeding season, it can also be found there in wetlands. In Southeast Asia, more forested and more humid areas are inhabited.
Systematics
Despite the large distribution area of the species, only two subspecies are distinguished, namely the nominate form H. f. fasciatus and the smaller subspecies H. f, which occurs only on some of the Lesser Sunda Islands and is marked darker on the lower abdomen and legs . renschi .
The closest relative of the Bonelli's eagle is the African Bonelli's eagle ( H. spilogaster ), which in the past was mostly regarded as a subspecies of the Bonelli's eagle. Ferguson-Lees & Christie separate both forms as separate species and consider them to be superspecies . The molecular genetic studies by Lerner & Mindell support the species status of both forms; the genetic distances between H. fasciatus and H. spilogaster were even somewhat larger than those between other twin species among the birds of prey, such as between the Lesser Spotted Eagle and the Greater Spotted Eagle or between the Little Eagle and the Australian Great Eagle ( H. . morphnoides ). However, Lerner & Mindell point out the need for further research.
The system of the subfamily Aquilinae is currently in a state of upheaval, the genus Hieraaetus is not a monophylum according to the available investigations and therefore probably not durable (see article Aquilinae ). Among other things, a merger of the genus with the genus Aquila is therefore proposed, so that the species can also be found in the more recent literature under the scientific name Aquila fasciata .
Hunting style and diet
Bonelli's eagles are flexible and, for a bird of this size, extremely agile and fast hunters, the hunting style often resembles that of the hawk . Bonelli's eagles often hunt mammals or birds on the ground from a covered hide, birds are pursued longer after they have blown up. Other hunting methods include thrusting down from high circles and searching for flights close to rock faces, with couples often hunting together. Bonelli's eagles usually strike their prey close above or on the ground.
The food consists of a large number of small to medium-sized vertebrates in accordance with the flexible hunting method and ranges in birds from blackbirds to gray geese , storks or collared bustards and in mammals from house rats to hares ; and reptiles are frequently caught. However, the majority of the prey consists of medium-sized birds such as pigeons , corvids, and fowl and mammals of similar size.
The year-round study of the food in Provence consisted of 62.5% birds, 28.5% mammals, 8.5% reptiles and 0.4% amphibians . The most common prey there was the wild rabbit (14.8% of all prey), followed by the red-legged partridge (12.6%), the Mediterranean gull ( Larus michahellis ) (12.2%) and the magpie (11.3%). The captured reptiles were all indeterminate lizards ( Lacerta sp.).
From 1999 to 2001, remains of loot were collected in Cyprus all year round. The distribution of the prey among the individual groups of vertebrates largely corresponded to that in Provence; The prey spectrum consisted of 56.6% birds, 34.2% mammals and 9.2% reptiles. The most common prey there, however, was the chukar chicken (32.4% of all prey), followed by the black rat (31.9%), the wood pigeon (10.0%) and the hardun (9.0%).
Reproduction
The courtship begins in November or December, the courtship flight consists of high circles and wave flights over the nest area. The large nests are mostly built in rock walls, less often on trees. In southern Europe, eggs are laid from the beginning of February to mid-March. The clutch usually consists of two, more rarely one or three eggs , which are laid two to three days apart. The eggs are brownish to yellowish speckled on a white background to a very variable thickness, the spotting can also be completely absent. Eggs from Europe and North Africa measure an average of 68.8 × 53.8 mm and weigh an average of 112 g. The incubation takes place almost exclusively by the female, who is supplied with food by the male during this time. The breeding season is 37 to 40 days. The nestlings leave the eyrie after 62 to 70 days and are then provided with food by their parents for around eight weeks.
hikes
Adult Bonelli's eagles are pronounced resident birds and also spend the winter in or near the breeding area. After migrating from their parents' territory, young birds show an undirected migration (dispersion), which can also take place over distances of several hundred kilometers.
Existence and endangerment
The population in the western Palearctic without Algeria was estimated at only 1,500 to 2,200 pairs around the year 2000, making the species one of the rarest species of birds of prey in this area. There are no reliable population figures for the rest of the Middle East and Central and Southeast Asia, but Ferguson-Lees & Christie estimate the world population at just a little over 10,000 breeding pairs.
In southern Europe there has been a sustained decline in the population over the past few decades. In three Spanish and two French study areas, between 1970 and 1992, population decreases between 0.3% and 8.7% per year were found. The main reason for the decrease there is the illegal persecution by hunters and pigeon fanciers as well as death at power poles. No information on population development is available from the breeding areas in North Africa and Asia.
The IUCN regards the world population as not endangered ( least concern ). Due to the continuing decline in Europe, however, the species is considered here as endangered ( endangered ).
swell
Individual evidence
- ^ A b c J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London, 2001, ISBN 0-7136-8026-1 : p. 753.
- ↑ HRL Lerner, DP Mindell: Phylogeny of eagles, Old World vultures and other Accipitridae based on nuclear and mitochondrial DNA . Molecular Phylogenetics and Evolution 37; 2005: pp. 327-346.
- ^ D. Simeon, JL Wilhelm: Essai sur l'alimentation annuelle de l'Aigle de Bonelli Hieraaetus fasciatus en Provence. Alauda, 56, 1988: 226-237. Quoted in: T. Mebs & D. Schmidt: The birds of prey in Europe, North Africa and the Middle East. Franckh-Kosmos, Stuttgart 2006, ISBN 3-440-09585-1 : p. 224. In Provence, the steppe gull mentioned there does not occur, but the sister species Mediterranean gull , therefore corrected here.
- ↑ S. Iezekiel, DE Bakaloudis, CG Vlachos: The Diet of Bonelli's Eagle Hieraaetus fasciatus in Cyprus. In: RD Chancellor, B.-U. Meyburg (eds): Raptors Worldwide. WWGBP / MME, Budapest, 2004: pp. 581-587
- ↑ UN Glutz v. Blotzheim, KM Bauer & E. Bezzel: Handbook of the birds of Central Europe . Vol. 4th, 2nd edition, AULA-Verlag, Wiesbaden, 1989, ISBN 3-89104-460-7 : pp. 687-688
- ↑ T. Mebs & D. Schmidt: The birds of prey in Europe, North Africa and the Middle East. Franckh-Kosmos, Stuttgart 2006: p. 222
- ↑ Real, J., Manosa, S., Cheylan, G., Bayle, P., Cugnasse, J.-M., Sanchez JA, Carmona, D., Martinez, JE, Rico, L., Codina, J. , Del Amo, R. and Eguia, S .: A preliminary Demographic Approach to the Bonelli's Eagle Hieraaetus fasciatus Population decline in Spain and France. In: Meyburg, B.-U. & Chancellor, RD (eds.): Eagle Studies. WWGBP, Berlin, London, Paris, 1996 ISBN 3-9801961-1-9 : pp. 523-528
- ↑ Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004) (English)
literature
- J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London, 2001. pp. 244-245, 750-753, ISBN 0-7136-8026-1
- D. Forsman: The Raptors of Europe and the Middle East - A Handbook of Field Identification . T & AD Poyser, London, 1999, ISBN 0-85661-098-4
- T. Mebs & D. Schmidt: The birds of prey in Europe, North Africa and the Middle East. Franckh-Kosmos, Stuttgart 2006, ISBN 3-440-09585-1
Web links
- Aquila fasciata in the Red List of Threatened Species of the IUCN 2008. Posted by: BirdLife International, 2008. Accessed October 13 of 2008.
- Videos, photos and sound recordings of Hieraaetus fasciatus in the Internet Bird Collection
- Web of Conservation Biology Team - Bonelli's eagle, of the University of Barcelona
- Avibase record of Bonelli's eagle ( Hieraaetus fasciatus ) (Vieillot, 1822)
- Age and gender characteristics (PDF; 5.4 MB) by J. Blasco-Zumeta and G.-M. Heinze (eng.)
- Bonelli's feathers
