Animal Diversity Web

Ge­o­graphic Range

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

Habi­tat

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

Phys­i­cal De­scrip­tion

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)

• Other Physical Features
• endothermic
• bilateral symmetry

• Average mass

  3000 g

  105.73 oz

Re­pro­duc­tion

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

Lifes­pan/Longevity

• Range lifespan
  Status: wild

  56 (high) years

• Average lifespan
  Status: captivity

  56 years

  AnAge

Be­hav­ior

The Im­pe­r­ial Eagle is, for the most part, a soli­tary species. The one ex­cep­tion to this is seen dur­ing mi­gra­tions. Each eagle will leave in­di­vid­u­ally, but there is a ten­dency to gather into loose flocks of ten or more once the jour­ney has begun. Since it is a loose flock there isn't much or­ga­ni­za­tion to it, and the in­di­vid­u­als are free to come and go as they please. Dur­ing mi­gra­tion, the Im­pe­r­ial Eagle has been known to travel up to 8000 km in about six weeks to reach their new quar­ters.

When the Im­pe­r­ial Eagle flies, it soars on level wings. It glides through the air with slightly low­ered pri­maries, and beats its wings with a heavy, flop­ping ac­tion. Its be­hav­ior tends to be rather slug­gish over long pe­ri­ods of time, but when hunt­ing or in high flight it can move re­mark­ably fast. (Chan­ning 2000, Pe­ter­son 1993)

• Key Behaviors
• flies
• motile

Com­mu­ni­ca­tion and Per­cep­tion

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

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)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

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)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

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)

Con­ser­va­tion Sta­tus

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)

• IUCN Red List

  Vulnerable
  More information

• IUCN Red List

  Vulnerable
  More information

• US Federal List

  No special status

• CITES

  Appendix I

Other Com­ments

The Im­pe­r­ial Eagle used to be con­sid­ered a species con­tain­ing two races. One race lived in the Iber­ian penin­sula, while the other lived in cen­traleast­ern Eu­rope and Asia. In re­cent times, how­ever, ev­i­dence has been found sug­gest­ing that the two races are ac­tu­ally sep­a­rate species. The race that lived in the Iber­ian penin­sula is now known as the Span­ish Im­pe­r­ial Eagle, or Aquila adal­berti, while Aquila he­li­aca con­tin­ues to be known sim­ply as the Im­pe­r­ial Eagle. (Here­dia 1996)

Con­trib­u­tors

Jeff Gour (au­thor), Mil­ford High School, George Camp­bell (ed­i­tor), Mil­ford High School.

Ref­er­ences

1988. Eagle. Pp. 2-5 in The World Book En­cy­clo­pe­dia. Chicago: World Book, Inc..

Bologna, G. 1978. Simon and Schus­ter’s Guide to Birds. New York: Simon and Schus­ter Pub­li­ca­tions.

Chan­ning, K. 2000. "The Im­pe­r­ial Ea­gle-Aquila he­li­aca" (On-line). Ac­cessed Oc­to­ber 2, 2000 at http://​www.​hawk-conservancy.​org/​priors/​sparks.​htm.

Here­dia, B. 1996. "In­ter­na­tional Ac­tion Plan for the Im­pe­r­ial Eagle" (On-line). Ac­cessed No­vem­ber 16, 2000 at http://​europa.​eu.​int/​comm/​environment/​nature/​directive/​birdactionplan/​aquilaheliaca.​htm.

Pe­ter­son, R., G. Mount­fort, P. Hol­lom. 1993. Birds of Britain and Eu­rope. New York: Houghton Mif­flin Com­pany.

Wyss, H. 1997. Eagle: A Por­trait of the An­i­mal World. New York: Smith­mark.