Eagles are not a natural group but denote essentially any kind of bird of prey large enough to hunt sizeable (about 50 cm long or more overall)vertebrates.
Eagles are large, powerfully-builtbirds of prey, with heavy heads and beaks. Even the smallest eagles, such as thebooted eagle (Hieraaetus pennatus), which is comparable in size to acommon buzzard (Buteo buteo) orred-tailed hawk (B. jamaicensis), have relatively longer and more evenly broad wings, and more direct, faster flight, despite the reduced size of their aerodynamic feathers. Most eagles are larger than any otherraptors, apart from somevultures. The smallest species of eagle is theGreat 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 hookedbeaks for ripping flesh from their prey, strong, muscular legs, and powerfultalons.
The beak is typically heavier than that of most other birds of prey. Eagles' eyes are extremely powerful. It is estimated that thewedge-tailed eagle has avisual acuity twice that of a typical human.[3][4][5] This acuity enables eagles to spot potential prey from a very long distance. This keen eyesight is primarily attributed to their extremely large pupils which ensure minimaldiffraction (scattering) of the incoming light. Like most diurnal raptors, eagles have little ability to seeultraviolet light.[6] The female of all known species of eagles is larger than the male.[7][8]
Eagles normally build their nests, calledeyries, 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 parents take no action to stop the killing.[9][10]It is said[by whom?] that eagles fly above clouds but this is not true.[citation needed] Eagles fly during storms and glide from the wind's pressure. This saves the bird's energy. Due to the size and power of many eagle species, they are ranked at the top of the food chain asapex predators in the avian world. The type of prey varies by genus. TheHaliaeetus andIcthyophaga eagles prefer to capture fish, though the species in the former often capture various animals, especially otherwater birds, and are powerfulkleptoparasites of other birds. The snake and serpent eagles of the generaCircaetus,Terathopius, andSpilornis predominantly prey on the great diversity ofsnakes found in the tropics of Africa and Asia. The eagles of the genusAquila are often the top birds of prey in open habitats, taking almost any medium-sizedvertebrate they can catch. WhereAquila eagles are absent, other eagles, such as thebuteonineblack-chested buzzard-eagle of South America, may assume the position of top raptorial predator in open areas. Many other eagles, including the species-rich genusSpizaetus, live predominantly in woodlands and forests. 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 on 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.[11]
Thebald 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.[12][13] However, a few eagles may target prey considerably heavier than themselves; such prey is too heavy to fly with, thus it is either eaten at the site of the kill or taken in pieces back to a perch or nest.Golden andcrowned eagles have killedungulates weighing up to 30 kg (66 lb) and amartial eagle even killed a 37 kg (82 lb)duiker, 7–8 times heavier than the preying eagle.[11]: 67–68 [14] Authors on birdsDavid 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):[15]
An Eagle named in honor of Abraham Lincoln and was the mascot of 8th Wisconsin Infantry Regiment, at the time of the U.S. Centennial
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 thecondors and some of theOld World vultures are markedly larger. It is regularly debated[according to whom?] 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 largeharpy eagle, have relatively short wingspans, a feature necessary for being able to maneuver in quick, short bursts through densely forested habitats.[11] Eagles in the genusAquila, found almost exclusively in open country, are noted for their ability to soar, and have relatively long wings for their size.[11]
These lists of the top five eagles are based on weight, length, and wingspan, respectively. Unless otherwise noted by reference, the figures listed are the median reported for each measurement in the guideRaptors of the World[16] in which only measurements that could be personally verified by the authors were listed.[11]
The eagles are generally distributed in all types of habitats and nearly all parts of the world. The birds can be found in northern tundra to tropical rainforests and deserts. In North America, bald eagles and golden eagles are very common.
Eagles are often informally divided into four groups.[a][22]
The snake eagles are placed in the subfamilyCircaetinae. The fish eagles, booted eagles, and harpy eagles have traditionally been placed in the subfamilyButeoninae together with the buzzard-hawks (buteonine hawks) and harriers. Some authors may treat these groups as tribes of the Buteoninae; Lerner & Mindell[23] proposed separating the eagle groups into their own subfamilies ofAccipitridae.
The fish eagles have a close genetic relationship withHaliastur andMilvus; the whole group is only distantly related to theButeo group.[24]
Fish eagles exist in every continent throughout the world, except for South America.[25]
Although fish eagles can be found in many different places around the world, they have been classified as "Near Threatened". Reasons such as overfishing, pollution, habitat destruction, and the use of pesticides have contributed to the species' rapid population drop.[26]
Eutriorchis (subfamily Gypaetinae or Circaetinae).
Despite filling the niche of a snake eagle, genetic studies suggest that theMadagascar serpent eagle (Eutriorchis) is not related to them.[24]
Over several decades, a great deal of research has been done on the Snake-eagle's diet, which is mainly made up of reptiles, especially snakes. When it comes to catching snakes, it is generally accepted that the bird exhibits generalist feeding behavior, which means it does not hunt down specific types of snakes but rather feeds on them depending on their availability in the wild.[28]
Harpy eagles[22] or "giant forest eagles"[21] 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, 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)
Harpia harpyja,harpy eagle ― Central and South America.
Morphnus guianensis,crested eagle ― Central and South America.
Harpyopsis novaeguineae,Papuan eagle ― New Guinea.
Martial eagle in NamibiaPhilippine eagle (Pithecophaga jefferyi) in Southern PhilippinesWedge-tailed eagle in AustraliaEastern imperial eagle in Israel
Major new research into eagletaxonomy suggests that the important generaAquila andHieraaetus 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 toLophaetus orIctinaetus.[23]
The modern English term for the bird is derived fromLatin:aquila by way ofFrench:aigle. The origin ofaquila is unknown, but it is believed to possibly derive fromaquilus (meaning dark-colored, swarthy, or blackish) as a reference to the plumage of eagles.
In the southern part ofFinland, near theGulf of Finland, is the town ofKotka, which literally means "eagle", while the town ofL'Aquila in the central part ofItaly literally means "the eagle".
The sculpture of eagle at the top of the fountain atPlac Orła Białego inSzczecin, Poland
In Britain before 1678,eagle referred specifically to thegolden eagle, with the other native species, thewhite-tailed eagle, being known aserne. The modern name "golden eagle" foraquila chrysaetos was introduced by the naturalistJohn Ray.[29]
The village ofEagle inLincolnshire,England, has nothing to do with the bird; its name is derived from the Old English words for "oak" and "wood" (compareOakley).[30]
Representation of an eagle atRio Carnival, 2014Garuda, thevahana (mount) ofVishnu, depicted with an eagle's beak and wings
In the ancientSumerian mythology, the mythical kingEtana was said to have been carried intoheaven by an eagle.[31] Classical writers such asLucan andPliny the Elder claimed that the eagle was able to look directly at the sun, and that they forced their fledglings to do the same. Those that blinked would be cast from the nest. This belief persisted until theMedieval era.[32]
The eagle is the patron animal of theancient Greek godZeus. In particular, Zeus was said to have taken the form of an eagle in order to abductGanymede, and there are numerous artistic depictions of the eagle Zeus bearing Ganymede aloft, from Classical times up to the present (see illustrations in theGanymede (mythology) page.)[33]
Eagles appear metaphorically in many translations of theOld Testament. God is spoken of as carrying Israel on "eagles' wings" inExodus 19:4,Isaiah 40:31 compares those who wait on the Lord to flying eagles, andPsalm 103 mentions renewing one's youth "as the eagle". In explaining this rejuvenation,Augustine of Hippo says in his commentary on thePsalms that eagles' beaks overgrow as they age and that they break them against rocks to restore them.[34] The translation, however, is uncertain: the word in the Hebrew,נשר, can also be translatedvulture,[35] and is listed alongside specific kinds of vulture inLeviticus' discussion ofunclean animals.
The eagle is also often used inChristian iconography to represent theGospel of John,[36] andeagle-shaped lecterns are common inAnglican and someRoman Catholic churches.[37] The eagle was believed to be able to look directly into the sun in the same way that the Gospel of John looks directly at Jesus' divinity, and the great distances the eagle flies represent the spread of the gospel to the ends of the earth.
The United Stateseagle feather law stipulates that only individuals of certifiableNative American ancestry enrolled in a federally recognized tribe are legally authorized to obtain eagle feathers forreligious orspiritual reasons.[38] In Canada, thepoaching of eagle feathers for the booming U.S. market has sometimes resulted in the arrests of First Nations person for the crime.[39]
TheMoche people of ancientPeru worshiped the eagle and often depicted eagles in their art.[40] The golden eagle was sacred to theAztec godHuitzilopochtli while the harpy eagle was sacred toQuetzalcoatl.[41]
Eagles are an exceptionally common symbol in heraldry, being considered the "King of Birds" in contrast to thelion, the "King of Beasts". Whereas the lion (e.g. England) usually represents authority, the eagle is the symbol of power. They are particularly popular in Germanic countries such as Austria, due to their association with theHoly Roman Empire. The eagle of the Holy Roman Empire was two-headed, supposedly representing the two divisions,East andWest, of the old Roman Empire. This motif, derived from the Byzantine (Eastern Roman) Empire was also adopted by theRussian Empire and is still featured in theFlag of Albania. The Roman eagle was preceded by the eagle ofPtolemaic Egypt and theAchaemenid Empire. In the coat of arms ofKotka, Finland, the eagle is depicted carrying ananchor and thecaduceus on its feet.
Heraldic eagles are most often founddisplayed, i.e. with their wings and legs extended. They can also occurclose, i.e. with their wings folded, orrising, i.e. about to take flight. The heads, wings, and legs of eagles can also be found independently.
Eagles symbolize strength, courage, and independence and are commonly found in the heraldry of many nations across the world. Albania, Andorra, Armenia, Austria, Dagestan, Egypt, Germany, Ghana, Indonesia, Iraq, Jordan, Kazakhstan, Mexico, Montenegro, Nigeria, the Philippines, Poland, Palestine, Panama, Russia, Romania, Serbia, South Sudan, Somaliland, Syria, the United States of America, Yemen, Zambia, and Zimbabwe are the nations whose coats of arms feature an eagle. The eagle's continuing significance and worldwide appeal as a forceful symbol in national identity and imagery is demonstrated by its widespread usage.[42]
^de Borhegyi, Carl (30 October 2012). "Evidence of Mushroom Worship in Mesoamerica". The Yucatan Times. Archived from the original on 12 September 2014. Retrieved 11 September 2014.
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