Most of the sixty species of eagles are from Eurasia and Africa. Outside this area, just fourteen species can be found – two in North America, nine in Central and South America, and three in Australia.
Eagles are large, powerfully built birds of prey, with a heavy head and beak. Even the smallest eagles, like the booted eagle (Aquila pennata) (which is comparable in size to a common buzzard (Buteo buteo) or red-tailed hawk (B. jamaicensis)), have relatively longer and more evenly broad wings, and more direct, faster flight – despite the reduced size of aerodynamic feathers. Most eagles are larger than any other raptors apart from some vultures. The smallest species of eagle is the South Nicobar serpent eagle (Spilornis klossi), at 450 g (1 lb) and 40 cm (16 in). The largest species are discussed below. Like all birds of prey, eagles have very large hooked beaks for tearing flesh from their prey, strong muscular legs, and powerful talons. The beak is typically heavier than that of most other birds of prey. Eagles' eyes are extremely powerful, having up to 3.6 times human acuity for the martial eagle, which enables them to spot potential prey from a very long distance. This keen eyesight is primarily attributed to their extremely large pupils which ensure minimal diffraction (scattering) of the incoming light. The female of all known species of eagle is larger than the male.
Eagles normally build their nests, called eyries, in tall trees or on high cliffs. Many species lay two eggs, but the older, larger chick frequently kills its younger sibling once it has hatched. The dominant chick tends to be the female, as they are bigger than the male. The parents take no action to stop the killing.
Due to the size and power of many eagle species, they are ranked at the top of the food chain as apex predators in the avian world. The type of prey varies from genus to genus. The Haliaeetus and Ichthyophaga eagles prefer to capture fish, though the species in the former often capture various animals, especially other water birds, and are powerful kleptoparasites of other birds. The snake and serpent eagles of the genera Circaetus, Terathopius and Spilornis predominantly prey on the great diversity of snakes that are found in the tropics of Africa and Asia. The eagles of the genus Aquila are often the top birds of prey in open habitats, taking almost any medium-sized vertebrate they can catch. Where Aquila eagles are absent, other eagles, such as the buteonine black-chested buzzard-eagle of South America, may assume the position of top raptorial predator in open areas. Many other eagles, including the species-rich Spizaetus genus, live predominantly in woodlands and forest. These eagles often target various arboreal or ground-dwelling mammals and birds, which are often unsuspectingly ambushed in such dense, knotty environments. Hunting techniques differ among the species and genera, with some individual eagles having engaged in quite varied techniques based their environment and prey at any given time. Most eagles grab prey without landing and take flight with it so the prey can be carried to a perch and torn apart. The bald eagle is noted for having flown with the heaviest load verified to be carried by any flying bird, since one eagle flew with a 6.8 kg (15 lb) mule deer fawn. However, a few eagles may target prey considerably heavier than themselves; such prey is too heavy to fly with and thus it is either eaten at the site of the kill or taken in pieces back to a perch or nest. Golden and crowned eagles have killed ungulates weighing up to 30 kg (66 lb) and a martial eagle even killed a 37 kg (82 lb) duiker, 7–8 times heavier than the predating eagle. Authors on birds David Allen Sibley, Pete Dunne and Clay Sutton, described the behavioral difference between hunting eagles and other birds of prey thus (in this case the bald and golden eagles as compared to other North American raptors):
They have at least one singular characteristic. It has been observed that most birds of prey look back over their shoulders before striking prey (or shortly thereafter); predation is after all a two-edged sword. All hawks seem to have this habit, from the smallest kestrel to the largest Ferruginous – but not the Eagles.
Among the eagles are some of the largest birds of prey: only the condors and some of the Old World vultures are markedly larger. It is regularly debated which should be considered the largest species of eagle. They could be measured variously in total length, body mass or wingspan. Different lifestyle needs among various eagles result in variable measurements from species to species. For example, many forest-dwelling eagles, including the very large harpy and Philippine eagles, have relatively short wingspans, a feature necessary for being able to maneuver in quick, short bursts through dense forested habitats. On the other hand, eagles in the genus Aquila are found almost strictly in open country, are superlative soarers, and have relatively long wings for their size.
Here are lists of the top five eagles going on weight, length and, lastly, wingspan. Unless otherwise noted via reference, the figures listed are the median reported for each measurement in the guide Raptors of the World (Ferguson-Lees, et al.), in which only measurements that could be personally verified by the authors were listed.
|Rank||Common name||Scientific name||Body mass|
|1||Steller's sea eagle||Haliaeetus pelagicus||6.7 kilograms (15 lb)|
|2||Philippine eagle||Pithecophaga jefferyi||6.35 kg (14.0 lb)|
|3||Harpy eagle||Harpia harpyja||5.95 kg (13.1 lb)|
|4||White-tailed eagle||Haliaeetus albicilla||4.8 kg (11 lb)|
|5||Martial eagle||Polemaetus bellicosus||4.6 kg (10 lb)|
|Rank||Common name||Scientific name||Total length|
|1||Philippine eagle||Pithecophaga jefferyi||100 cm (3 ft 3 in)|
|2||Harpy eagle||Harpia harpyja||95.5 cm (3 ft 2 in)|
|3||Wedge-tailed eagle||Aquila audax||95.5 cm (3 ft 2 in)|
|4||Steller's sea eagle||Haliaeetus pelagicus||95 cm (3 ft 1 in)|
|5||Crowned eagle||Stephanoaetus coronatus||87.5 cm (2 ft 10 in)|
|Rank||Common name||Scientific name||Median wingspan|
|1||White-tailed eagle||Haliaeetus albicilla||218.5 cm (7 ft 2 in)|
|2||Steller's sea eagle||Haliaeetus pelagicus||212.5 cm (7 ft 0 in)|
|3||Wedge-tailed eagle||Aquila audax||210 cm (6 ft 11 in)|
|4||Golden eagle||Aquila chrysaetos||207 cm (6 ft 9 in)|
|5||Martial eagle||Polemaetus bellicosus||206.5 cm (6 ft 9 in)|
- Nearctic (USA and Canada): golden eagle (also found in Palearctic), bald eagle
- Neotropical (Central and South America): Spizaetus (4 species), solitary eagles (2 spp.), harpy eagle, crested eagle, black-chested buzzard-eagle
The snake eagles are placed in the subfamily Circaetinae. The fish eagles, booted eagles, and harpy eagles have traditionally been placed in the subfamily Buteoninae together with the buzzard-hawks (buteonine hawks) and harriers. Some authors may treat these groups as tribes of the Buteoninae; Lerner & Mindell proposed separating the eagle groups into their own subfamilies of Accipitridae.
Sea eagles or fish eagles take fish as a large part of their diets, either fresh or as carrion.
Some authors include Gypohierax angolensis, the "vulturine fish eagle" (also called the palm-nut vulture) in this group. However, genetic analyses indicate it is related to a grouping of Neophron–Gypaetus–Eutriorchis (Egyptian vulture, bearded vulture (lammergeier), and Madagascan serpent eagle).
See comments under eagle species for changes to the composition of these genera.
Snake or serpent eagles are, as the name suggests, adapted to hunting reptiles.
- Eutriorchis (subfamily Gypaetinae or Circaetinae).
Harpy eagles or "giant forest eagles" are large eagles that inhabit tropical forests. The group contains two to six species, depending on the author. Although these birds occupy similar niches, and have traditionally been grouped together, they are not all related: the solitary eagles are related to the black-hawks, and the Philippine eagle to the snake eagles.
- Harpy eagles (proposed subfamily Harpiinae)
- Philippine eagle
- Pithecophaga jefferyi, Philippine eagle ― Philippines.
- Solitary eagles
Major new research into eagle taxonomy suggests that the important genera Aquila and Hieraaetus are not composed of nearest relatives, and it is likely that a reclassification of these genera will soon take place, with some species being moved to Lophaetus or Ictinaetus.
- Bonelli's eagle and the African hawk-eagle have been moved from Hieraaetus to Aquila.
- Either the greater spotted eagle and lesser spotted eagle should move from Aquila to join the long-crested eagle in Lophaetus, or, perhaps better, all three of these species should move to Ictinaetus with the black eagle.
- The steppe eagle and tawny eagle, once thought to be conspecific, are not even each other's nearest relatives.
- Subfamily Buteoninae – hawks (buzzards), true eagles and seaeagles
- Genus Geranoaetus
- Black-chested buzzard-eagle, Geranoaetus melanoleucus
- Genus Harpyhaliaetus
- Genus Morphnus
- Crested eagle, Morphnus guianensis
- Genus Harpia
- Harpy eagle, Harpia harpyja
- Genus Pithecophaga
- Philippine eagle, Pithecophaga jefferyi
- Genus Harpyopsis
- Papuan eagle, Harpyopsis novaeguineae
- Genus Spizaetus
- Genus Nisaetus - previously included in Spizaetus
- Changeable or crested hawk-eagle, N. cirrhatus
- Flores hawk-eagle N. floris - earlier a subspecies, S. c. floris
- Sulawesi hawk-eagle, N. lanceolatus
- Mountain hawk-eagle, N. nipalensis
- Legge's hawk-eagle, Nisaetus kelaarti - previously a race of S. nipalensis
- Blyth's hawk-eagle, N. alboniger
- Javan hawk-eagle, N. bartelsi
- (Northern) Philippine hawk-eagle, N. philippensis
- Pinsker's hawk-eagle (Southern Philippine hawk-eagle), Nisaetus pinskeri - earlier S. philippensis pinskeri
- Wallace's hawk-eagle, N. nanus
- Changeable or crested hawk-eagle, N. cirrhatus
- Genus Lophaetus
- Long-crested eagle, Lophaetus occipitalis – possibly belongs in Ictinaetus
- Genus Stephanoaetus
- Crowned eagle, Stephanoaetus coronatus
- Genus Polemaetus
- Martial eagle, Polemaetus bellicosus
- Genus Hieraaetus
- Genus Harpagornis (extinct)
- Genus Lophotriorchis
- Rufous-bellied hawk-eagle, L. kienerii
- Genus Aquila
- Bonelli's eagle, Aquila fasciata – formerly Hieraaetus fasciatus
- African hawk-eagle, A. spilogaster – formerly in Hieraaetus
- Cassin's hawk-eagle, A. africana – formerly in Hieraaetus or Spizaetus genera
- Golden eagle, A. chrysaetos
- Eastern imperial eagle, A. heliaca
- Spanish imperial eagle A. adalberti
- Steppe eagle, A. nipalensis
- Tawny eagle, A. rapax
- Greater spotted eagle, A. clanga – to be moved to Lophaetus or Ictinaetus
- Lesser spotted eagle, A. pomarina – to be moved to Lophaetus or Ictinaetus
- Indian spotted eagle, A. hastata – to be moved to Lophaetus or Ictinaetus
- Verreaux's eagle, A. verreauxii
- Gurney's eagle, A. gurneyi
- Wahlberg's eagle, A. wahlbergi - to be moved to Hieraaetus
- Wedge-tailed eagle, A. audax
- Genus Ictinaetus
- Black eagle, Ictinaetus malayensis
- Genus Haliaeetus
- Genus Ichthyophaga
- Genus Geranoaetus
- Subfamily Circaetinae: snake-eagles
- Genus Terathopius
- Bateleur, Terathopius ecaudatus
- Genus Circaetus
- Genus Dryotriorchis
- Congo serpent eagle, D. spectabilis
- Genus Spilornis
- Genus Eutriorchis
- Madagascar serpent eagle, Eutriorchis astur
- Genus Terathopius
Eagles in culture
The modern English term for the bird is derived from Latin: aquila by way of French: aigle. The origin of aquila is unknown, but it is believed to possibly derive from either aquilus (meaning dark-colored, swarthy, or blackish) as a reference to the plumage of eagles or from aquilo (meaning north wind).
Old English used the term earn, related to Scandinavia's ørn / örn. It is similar to other Indo-European terms for "bird" or "eagle", including Greek: ὄρνις (ornís), Russian: орёл (orël), and Welsh: eryr. The Albanian word for eagle is shqiponjë, deriving from the root shqipe.
In Britain before 1678, eagle referred specifically to the golden eagle, with the other native species, the white-tailed eagle, being known as erne. The modern name "golden eagle" for aquila chrysaetos was introduced by the naturalist John Ray.
Religion and folklore
The eagle is also the patron animal of the ancient Greek god Zeus. In particular, Zeus was said to have taken the form of an eagle in order to abduct Ganymede, and there are numerous artistic depictions of the eagle Zeus bearing Ganymede aloft, from Classical times up to the present (see illustrations in the Ganymede (mythology) page.)
The United States eagle feather law stipulates that only individuals of certifiable Native American ancestry enrolled in a federally recognized tribe are legally authorized to obtain eagle feathers for religious or spiritual reasons. In Canada, the poaching of eagle feathers for the booming U.S. market has sometimes resulted in the arrests of First Nations person for the crime.
The eagle is a common form in the Anglican tradition, often used to support the Bible because of the symbolism of spreading the gospel over the world. Additional symbolic meanings for "eagle" include the pronouncements to the Israelites in Exodus 19:4; Psalms 103:5 and Isaiah 40:31.
In Hinduism, Garuda is a lesser divinity, usually the mount (vahanam) of Vishnu. Garuda is depicted as having the golden body of a strong man with a white face, red wings, and an eagle's beak and with a crown on his head. This ancient deity was said to be massive, large enough to block out the sun.
Eagles are an exceptionally common symbol in heraldry, being considered the "King of Birds" in contrast to the lion, the "King of Beasts". They are particularly popular in Germanic countries, due to their association with the Roman Empire and its claimed successor the Holy Roman Empire. The eagle of the Holy Roman Empire was two-headed, supposedly representing the two divisions, East and West, of the old Roman Empire.
Heraldic eagles are most often found displayed, i.e. with their wings and legs extended. They can also occur close, i.e. with their wings folded, or rising, i.e. about to take flight. The heads, wings, and legs of eagles can also be found independently.
- The coat of arms and flag of Albania has a black double-headed eagle. Furthermore, the eagle gives Albania its name (in Albanian Shqiperia means Land of the eagles) and Albanians call themselves shqipetar or shqipe meaning eagles.
- The coat of arms of Armenia has a gold eagle and a lion.
- The coat of arms of Austria has a black eagle.
- The coat of arms of the Czech Republic integrates the symbols of Moravia and Silesia (both with female eagles in their emblems – red-and-white chequered and black respectively) with Bohemia's lion.
- The coat of arms of Egypt is a golden eagle looking towards the viewer's left. It is taking from the golden Eagle of Saladin founded on Saladin Citadel of Cairo.
- The coat of arms of Germany has a black eagle.
- The coat of arms of Ghana has two golden eagles holding it.
- The coat of arms of Iceland has an eagle holding it, as well as a dragon, a bull and a giant.
- The coat of arms of Indonesia has an eagle-like garuda carrying a shield on its neck and a banner on its feet.
- The coat of arms of Iraq has the golden Eagle of Saladin.
- The coat of arms of Mexico has a golden eagle perched upon a cactus devouring a snake.
- The coat of arms of Moldova consists of a stylized eagle holding a cross in its beak and a sceptre and a branch in its claws.
- The coat of arms of Montenegro represents the two-headed eagle in flight.
- The coat of arms of Navarre/Basque Country Kingdom has a black eagle.
- The coat of arms of Nigeria has a red eagle on top.
- The coat of arms of Palestine has the golden Eagle of Saladin.
- The coat of arms of Panama has a harpy eagle.
- The coat of arms of the Philippines has the bald eagle of the United States as a symbol of its colonial past, but the monkey-eating eagle is the de jure national bird of the country.
- The coat of arms of Poland has a white eagle with a golden beak and talons wearing a golden crown.
- The coat of arms of Romania has a golden aquila holding a cross in its beak and a mace and a sword in its claws.
- The coat of arms of Russia has a gold double-headed eagle.
- The coat of arms of Serbia has a white bicephalic eagle of the House of Nemanjić.
- The coat of arms of Syria formerly had the eagle of Saladin.
- The Great Seal of the United States has a bald eagle.
- The coat of arms of Yemen depicts a golden eagle with a scroll between its claws.
- The coat of arms of Zambia has an orange red eagle on top.
- The Polish and the Serbian eagles are distinguished by their white color.
- The Ptolemaic rulers of Egypt used it as their seal.
- Napoleon I used the Roman golden eagle as the symbol of his new French empire.
- Persian Empire: the symbol of the Persian Army was an eagle.
- The Romans used it on the standards of their armies. From this derives:
- The late Byzantine Empire chose a two-headed golden eagle as its symbol. It is popularly that one head symbolised ancient Rome, and the other head symbolized "new Rome" at Constantinople. From this derives:
- After his crowning as the new Roman Emperor, Charlemagne adopted the ancient Roman eagle as his own symbol. The Holy Roman Empire born of his kingdom took the eagle. From this derives:
- The Austrian Empire had a two-headed eagle as its symbol. After the abolition of Austria-Hungary, Austria took as its symbol a one-headed eagle in the modern coat of arms of Austria.
- Prussia, and later Germany have used a black eagle as their national symbol.
- The Spanish Catholic monarchs, Isabella and Ferdinand, used the eagle as a part of the royal shield representing Saint John the Evangelist. The eagle was again on the Spanish shield under the Francoist regime and the transition to Democracy (1939–1981).
- The Seljuk and Ottoman Turks both used a double-headed eagle in their coats-of-arms.
- During the 1930s and 1940s, Adolf Hitler's Nazi Germany used a black eagle with its wings outstretched and clutching a swastika as its insignia.
- "There are four major groups of eagles: fish eagles, booted eagles, snake eagles and giant forest eagles."
- del Hoyo, J.; Elliot, A. & Sargatal, J. (editors). (1994). Handbook of the Birds of the World Volume 2: New World Vultures to Guineafowl. Lynx Edicions. ISBN 84-87334-15-6
- Shlaer, Robert (1972). "An Eagle's Eye: Quality of the Retinal Image" (PDF). Science 176 (4037): 920–922. doi:10.1126/science.176.4037.920. PMID 5033635. Retrieved 2012-04-16.
- Leclerc, Georges Louis, Comte de Buffon (2010). The Natural History of Birds: From the French of the Count de Buffon; Illustrated with Engravings, and a Preface, Notes, and Additions, by the Translator. Cambridge University Press. pp. 60–. ISBN 978-1-108-02298-9.
- Grambo, Rebecca L. (2003). Eagles. Voyageur Press. ISBN 978-0-89658-363-4.
- Grambo, Rebecca L (2003). Eagles. Voyageur Press. p. 32. ISBN 978-0-89658-363-4.
- Stinson, Christopher H (1979). "On the Selective Advantage of Fratricide in Raptors". Evolution 33 (4): 1219–1225. doi:10.2307/2407480.
- Ferguson-Lees, J.; Christie, D. (2001). Raptors of the World. London: Christopher Helm. ISBN 0-7136-8026-1.
- "Amazing Bird Records". Trails.com. Retrieved 2012-07-20.
- Watson, Jeff (2011). The Golden Eagle: Second Edition. ISBN 978-0-30017-019-1.
- Sutton, C.; Dunne, P.; Sibley, D. (1989). Hawks in Flight: The Flight Identification of North American Migrant Raptors. Boston: Houghton Mifflin Harcourt. ISBN 0-3955-1022-8.
- del Hoyo, J; Elliot, A; Sargatal, J (1996). Handbook of the Birds of the World 3. Barcelona: Lynx Edicions. ISBN 84-87334-20-2.
- Gamauf, A., Preleuthner, M., and Winkler, H. (1998). "Philippine Birds of Prey: Interrelations among habitat, morphology and behavior" (PDF). The Auk 115 (3): 713–726. doi:10.2307/4089419.
- Morgan, A.M. "The spread and weight of the Wedge-tailed Eagle" (PDF). South Australian Ornithologist 11: 156–157.
- Wood, Gerald (1983). The Guinness Book of Animal Facts and Feats. ISBN 978-0-85112-235-9.
- Stalcup, Carolyn. "All About Eagles". The American Eagle Foundation. Retrieved 25 May 2014.
- Rutledge, Hope. "Eagles of the World". American Bald Eagle Information. Retrieved 11 June 2014. from Grambo, Rebecca L. (1999). Eagles. Voyageur Press, Inc.
- Lerner, H. R. L.; Mindell, D. P. (2005). "Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA". Molecular Phylogenetics and Evolution 37 (2): 327–346. doi:10.1016/j.ympev.2005.04.010. PMID 15925523.
- Lerner, Heather R. L.; Mindell, David P. (9 May 2006). "Accipitridae". The Tree of Life Web Project.
- Bouglouan, Nicole. "The booted eagles throughout the world: introduction". Oiseaux-birds. Retrieved 11 June 2014.
- Bunce, M. et al. (2005). "Ancient DNA Provides New Insights into the Evolutionary History of New Zealand's Extinct Giant Eagle". PLoS Biol 3 (1): e9. doi:10.1371/journal.pbio.0030009. PMC 539324. PMID 15660162.
- Larco Herrera, Rafael and Berrin, Kathleen (1997) The Spirit of Ancient Peru Thames and Hudson, New York, ISBN 0500018022
- Office of Law Enforcement. "National Eagle Repository". Mountain-Prairie Region. United States Fish and Wildlife Service. Archived from the original on 2007-10-10. Retrieved 2007-11-20.
- Sin, Lena (2006-04-30). "Charges laid in eagle-poaching case". The Province (CanWest MediaWorks Publications Inc.). Retrieved 2007-11-20.
- Psalm 103 in Augustine's commentary.
- Collinson, Martin. Splitting headaches? Recent taxonomic changes affecting the British and Western Palaearctic lists British Birds vol 99 (June 2006), 306–323
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- PBS Nature: Eagles
- PBS Video Episode: American Eagle
- Eagle photos on Oriental Bird Images
- Eagle videos on the Internet Bird Collection
- Web of the Conservation Biology Team-Bonelli's Eagle, of the University of Barcelona
- Decorah Eagles: 24/7 Live Webcam from The Raptor Resource Project
- EagleCAM: White-bellied Sea Eagles Live Webcam at Discovery Centre in Sydney, Australia