Aquilua heliaca can be found throughout southern Europe, from Greece to southern Russia. Here it can be found as far south as a line drawn from Cyprus to northwest India, and as far east as Central Siberia. It can also be found sparsely in Spain. In winter it migrates to northeast Africa (from Egypt to Kenya), India, and southeast China (Channing 2000).
Biogeographic Regions: palearctic (Native ); oriental (Native ); ethiopian (Native )
The Imperial Eagle is the second largest eagle to reside in Europe. It can grow to a length of about 0.92 meters. It can have a wingspan approaching 2.14 meters and have a mass of about 3.6 kilograms. Adults are black-brown in color. They have a pale golden crown and nape, and a grey base that extends to the tail. They also have very apparent white "braces" on their scapulars. Juveniles are paler and more variegated than the adults. They are yellow-brown with rump, wing, and tail patterns similar to the patterns of the Lesser Spotted, pale Spotted, Tawny and Steppe eagles. They are distinguished from these eagles, however, by the bolder streaks on their under-wings and body, the lack of a pale band under the wing-coverts, and their larger and more majestic build. Both the juveniles and adults have noticeably protruding head and long, parallel-edged wings. Like other eagles, they have strong legs and feet. Their feet include long, curved talons that they use to seize, kill and carry their prey. They also have large eyes that are located slightly to the side of the head. These eyes provide them with extremely keen eyesight, allowing them to spot prey from high in the air. (Peterson 1993, Wyss 1997, Eagle 1988)
Average mass: 3000 g.
Other Physical Features: endothermic ; bilateral symmetry
The Imperial Eagle tends to live in forests, where it will build a huge, conspicuous nest in an isolated tall tree. Old forests, and the forests in mountains, hills, and along rivers are all common habitats. It has, however, also been known to live in steppes, open landscapes, agricultural areas, and even semideserts. Imperial eagles hunt in open fields or wetlands. During migration, a variety of habitats are used, though they seem to prefer to winter in wetlands. (Heredia 1996, Peterson 1993)
Terrestrial Biomes: savanna or grassland ; forest
Habitat and Ecology
The Imperial Eagle, like other birds of prey, is a carnivore. Its main source of food is small mammals, such as rabbits and susliks (ground squirrels in the genus Spermophilus). It will also eat reptiles, including some poisonous snakes, and other birds, such as young magpies, waders, and ducks. It has been known to feed on some carrion as well, carrying off lambs that were already dead. It generally hunts by slowly flying around the open areas near the forest where it resides, staying just above the treetop level, and scanning for prey. Its excellent eyesight makes spotting prey easy. When it sees a suitable prey item it will drop down on it, using its talons to kill and carry the prey. It will also, on a few occasions, perch high on a tree near the edge of the forest, and drop on its prey from there. (Channing 2000, Eagle 1988)
Known prey organisms
This list may not be complete but is based on published studies.
Life History and Behavior
Perception Channels: visual ; tactile ; acoustic ; chemical
Status: wild: 56 (high) years.
Status: captivity: 56 years.
Lifespan, longevity, and ageing
Imperial Eagles are ready to breed for the first time when they are about four years old. When they reach this age, they find a mate whom they stay with for life. If one happens to die, however, the other will usually find a new mate and breed the next year. Every pair will build a nest, called an eyrie, in the top of a tree. These nests are generally made mainly with sticks, and are used only during the spring and summer months. Females will generally lay two eggs a year. Sometimes, however, they will lay three eggs, and on a few rare occasions they will lay four. These eggs have to be incubated for about forty-three days before they can hatch, and both parents will participate in the incubation. Even though two eggs are usually hatched, it is unusual for both eaglets, or baby eagles, to survive. One is usually born a couple days earlier than the other. This older, larger eaglet eats more than its share of food, and will repeatedly attack, often killing, the younger one. The young eagles are ready to fly when they are sixty days old. They stay near the nest, however, for an additional two weeks, and continue to be fed by the mother until they are ready to hunt for themselves. (Bologna 1978, Eagle 1988)
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Molecular Biology and Genetics
Statistics of barcoding coverage: Aquila heliaca
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1
The Imperial Eagle is classified as endangered at the European level, and vulnerable at the global level. There are several threats to its survival, and habitat alterations are probably the most critical. Several kinds of forestry operations in their breeding areas can seriously hurt its ability to survive and reproduce. These operations include, but aren't limited to, the cutting of forests for reafforestation with alien species, cutting of large, old trees in forests and along forest edges, and logging disturbances. Several other types of human disturbances can also be major limiting factors. The Imperial Eagle is a very sensitive species, and can easily be hurt by both intentional and unintentional interference. An example of intentional interference is hunting. Imperial Eagles are often shot during migrations. Examples of unintentional interference include the eagles ingesting poisons meant to control other species and flying into power lines, electrocuting themselves. (Heredia 1996)
US Federal List: no special status
CITES: appendix i
IUCN Red List of Threatened Species: vulnerable
IUCN Red List Assessment
Red List Category
Red List Criteria
Status in Egypt
Regular passage visitor and winter visitor?
CITES Appendix I and II. CMS Appendix I and II. It is legally protected in Armenia, Azerbaijan, Bulgaria, Croatia, Georgia, Greece, Hungary, Romania, Slovakia, Turkey and Ukraine. The Eastern Imperial Eagle Working Group was established in 1990. A European action plan was published in 1996 and its implementation reviewed in 2010 (Barov and Derhé 2011). Regional Action Plans have been published for the Balkan Peninsula (Stoychev et al. 2004) and for the Southern Caucasus (Horváth et al. 2006). The Eastern Imperial Eagle Management Guidelines for Hungary were published in 2005 and are under preparation for Slovakia(Kovács et al. 2006). Conservation Actions Proposed
Conduct surveys in Asia (particularly Russia and Kazakhstan) to determine population size and trends. Conduct surveys to identify breeding and wintering sites, and migration routes. Improve protection of species and sites. Implement beneficial forestry policies. Maintain large trees in open land and protect old woodland on slopes(B. Hallmann in litt. 1999). Prevent mortality from nest robbing, nest destruction, illegal trade, poisoning and electrocution on medium-voltage powerlines, as well as persecution in wintering grounds and migratory routes. Maintain feeding habitats by preserving traditional land use. Increase the availability of prey species by habitat management. Raise public awareness and involve stakeholders in conservation activities.
Relevance to Humans and Ecosystems
Although rare, Imperial Eagles have been known to attack humans who come too close to their nests. They may dive at a person who gets too close and strike at them with their talons. (Eagle 1988)
Imperial Eagles are beneficial to farmers and ranchers because they feed on rabbits and other small mammals. By eating these animals, the Imperial Eagle reduces their numbers, and thus reduces the damage they can do. This eagle also feeds on venomous reptiles, many of which have been known to cause serious harm to humans. (Channing 2000)
Eastern imperial eagle
The eastern imperial eagle (Aquila heliaca) is a large species of bird of prey that breeds from southeastern Europe to western and central Asia. Most populations are migratory and winter in northeastern Africa, and southern and eastern Asia. The Spanish imperial eagle, found in Spain and Portugal, was formerly lumped with this species, the name imperial eagle being used in both circumstances. However, the two are now regarded as separate species due to significant differences in morphology, ecology and molecular characteristics.
The eastern imperial eagle is a large eagle with a length of 72–90 cm (28–35 in), a wingspan of 1.8–2.16 m (5.9–7.1 ft) and a weight of 2.45–4.55 kilograms (5.4–10.0 lb). Females are about a quarter larger than males. It closely resembles the Spanish imperial eagle, but has far less white to the "shoulder" and it is slightly larger.
In Europe, the eastern imperial eagle is threatened with extinction. It has nearly vanished from many areas of its former range, e.g. Hungary and Austria. Today, the only European populations are increasing in the Carpathian basin, mainly the northern mountains of Hungary and the southern region of Slovakia. The breeding population in Hungary consists of about 105 pairs. The most western breeding population on the border between Austria and Czech republic consists of 15 - 20 pairs.
The monarchy of Austria-Hungary once chose the imperial eagle to be its heraldic animal, but this did not help this bird. The eagle's preferred habitat is open country with small woods; unlike many other species of eagle, it does not generally live in mountains, large forests or treeless steppes.
Eastern imperial eagles generally prefer to construct a nest in a tree which is not surrounded by other trees, so that the nest is visible from a considerable distance, and so that the occupants may observe the surroundings unobstructed. Tree branches are taken in order to build the nest, which is upholstered with grass and feathers. Very rarely it nests on cliffs or the ground.
In March or April the female lays two to three eggs. The chicks hatch after about 43 days and leave the nest after 60–77 days. Often, however, only one will survive to leave the nest, with the others dying before becoming fully fledged. In at least a part of its range, more than a third of all nesting attempts are entirely unsuccessful.
- BirdLife International (2013). "Aquila heliaca". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Meyburg, B. U. (1994). Eastern Imperial Eagle (Aquila heliaca). Pp. 194-195 in: del Hoyo, Elliott & Sargatal. eds. (1994). Handbook of the Birds of the World, vol. 2. ISBN 84-87334-15-6
- Sangster, George; Knox, Alan G.; Helbig, Andreas J. & Parkin, David T. (2002) Taxonomic recommendations for European birds. Ibis 144(1): 153–159. doi:10.1046/j.0019-1019.2001.00026.x PDF fulltext
- Cramp, S. & Simmons, K. E. L. (1980) Birds of the Western Palearctic, Vol. 2. Oxford University Press, Oxford.
- Padilla, J. A.; Martinez-Trancón, M.; Rabasco, A. & Fernández-García, J. L. (1999) The karyotype of the Iberian imperial eagle (Aquila adalberti) analyzed by classical and DNA replication banding. Cytogenetics and Cell Genetics 84: 61–66. doi:10.1159/000015216 (HTML abstract)
- Seibold, I.; Helbig, A. J.; Meyburg, B. U.; Negro, J. J. & Wink, M. (1996): Genetic differentiation and molecular phylogeny of European Aquila eagles (Aves: Falconiformes) according to cytochrome-b nucleotide sequences. In: Meyburg, B. U. & Chancellor, R. D. (eds): Eagle Studies: 1–15. Berlin: World Working Group on Birds of Prey.
- Raptors of the World by Ferguson-Lees, Christie, Franklin, Mead & Burton. Houghton Mifflin (2001), ISBN 0-618-12762-3
- Ali, Salim (1993). The Book of Indian Birds. Bombay: Bombay Natural History Society. ISBN 0-19-563731-3.
- Horváth M et al. 2010. Spatial variation in prey composition and its possible effect on reproductive success in an expanding eastern imperial eagle (Aquila heliaca) population. Acta Zoologica Academiae Scientiarum Hungaricae, 56, 187–200.
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