Booted eagles are

eagle Eagle is the common name for the golden eagle, bald eagle, and other birds of prey in the family of the Accipitridae. Eagles belong to several groups of Genus, genera, some of which are closely related. True eagles comprise the genus ''Aquila ( ...

s that have fully feathered tarsi. That is, their legs are covered with feathers down to the feet. Most other accipitrids have bare lower legs, scaled rather than feathered. They may be treated as an informal group, as distinct from "fish eagles" (or "sea eagles"), "snake eagles", and "giant forest eagles". They may also be treated as a formal taxon, either as a tribe (Aquililae) or subfamily ( Aquilinae). The booted eagles, sea eagles, harpy eagles and buteonine hawks are heavily built birds that have traditionally been classified together in the large subfamily Buteoninae. In 2005, Heather Lerner and David Mindell proposed separating the eagles into their own subfamilies Aquilinae, Haliaeetinae, and Harpiinae, leaving only the buteo–buteogallus clade in a more restricted Buteoninae. Included in the booted eagles are the genera ''Aquila'', ''Hieraaetus'' and ''Clanga''; all species described as "hawk eagles" including the genera '' Spizaetus'' and '' Nisaetus''; as well as assorted monotypical genera such as '' Oroaetus'', '' Lophaetus'', '' Stephanoaetus'', '' Polemaetus'', '' Lophotriorchis'' and '' Ictinaetus''.

Hawk eagles

''Aquila'' eagles

The genus '' Aquila'' is distributed across every continent but for

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. Up to 20 species have been classified in the genus but the taxonomic placement of some of the traditionally included species has recently been questioned. Traditionally, the ''Aquila'' eagles have been grouped superficially as largish, mainly brownish or dark-colored booted eagles that vary little in transition from their juvenile to their adult plumages. Genetic research has recently indicated a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

containing the near-circumpolar

golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known bird of pr ...

(''Aquila chrysaetos''),

Verreaux's eagle Verreaux's eagle (''Aquila verreauxii'') is a large, mostly African, bird of prey. It is also called the black eagle, especially in southern Africa, not to be confused with the black eagle (''Ictinaetus malayensis'') of south and southeast Asia. ...

(''A. verreauxii'') of Africa, Asian Gurney's eagle (''A. gurneyi'') and the Australian

wedge-tailed eagle The wedge-tailed eagle (''Aquila audax'') also known as the eaglehawk, is the largest bird of prey in the continent of Australia. It is also found in southern New Guinea to the north and is distributed as far south as the state of Tasmania. A ...

(''A. audax''). This identification of this particular clade has long been suspected based on similar morphological characteristics amongst these large-bodied species. More surprisingly, the smaller, much paler-bellied species pair Bonelli's eagle (''A. fasciatus'') and African hawk-eagle (''A. spilogaster''), previously included in the genus ''Hieraaetus'', have been revealed to be genetically much closer to the Verreaux's and golden eagle lineage than to other species traditionally included in the genus ''Aquila''. Other largish ''Aquila'' species, the

eastern imperial eagle The eastern imperial eagle (''Aquila heliaca'') is a large bird of prey that breeds in southeastern Europe and extensively through West and Central Asia. Most populations are migratory and winter in northeastern Africa, the Middle East and South a ...

(''A. heliaca''), the

Spanish imperial eagle The Spanish imperial eagle (''Aquila adalberti''), also known as the Iberian imperial eagle, the Spanish eagle or Adalbert's eagle, is a species of eagle native to the Iberian Peninsula. The binomial commemorates Prince Adalbert of Bavaria. Due ...

(''A. adaberti''), the

tawny eagle The tawny eagle (''Aquila rapax'') is a large bird of prey. Like all eagles, it belongs to the family ''Accipitridae''. Its heavily feathered legs mark it as a member of the subfamily Aquilinae, also known as booted eagles.Helbig, A. J., Kocum, ...

(''A. rapax'') and the

steppe eagle The steppe eagle (''Aquila nipalensis'') is a large bird of prey. Like all eagles, it belongs to the family Accipitridae. The steppe eagle's well-feathered legs illustrate it to be a member of the subfamily Aquilinae, also known as the "booted ...

s (''A. nipalensis''), are now thought to be separate, close-knit clade, which attained some similar characteristics to the golden eagle clade via convergent evolution.

Spotted eagles

Genetically, the "spotted eagles" ('' A. pomarina, A. hasata & A. clanga''), have been discovered to be more closely related to the

long-crested eagle The long-crested eagle (''Lophaetus occipitalis'') is an African bird of prey characterised by its shaggy crest of feathers. In the family Accipitridae which includes all the eagles, it is currently placed in a monotypic genus ''Lophaetus''. It ...

(''Lophaetus occipitalis'') and the

black eagle The black eagle (''Ictinaetus malaiensis'') is a bird of prey. Like all eagles, it is in the family Accipitridae, and is the only member of the genus ''Ictinaetus''. They soar over forests in the hilly regions of tropical and subtropical South a ...

(''Ictinaetus malaiensis''), and many generic reassignments have been advocated. Some authorities place the spotted eagles in a separate genus, '' Clanga''.

Hieraaetus

The genus ''

Hieraaetus The genus ''Hieraaetus'', sometimes known as small eagles or hawk-eagles, denotes a group of smallish eagles usually placed in the accipitrid subfamilies Buteoninae or Aquilinae. They are generally medium-sized birds of prey inhabiting Europ ...

'', including the

booted eagle The booted eagle (''Hieraaetus pennatus'', also classified as ''Aquila pennata'') is a medium-sized mostly migratory bird of prey with a wide distribution in the Palearctic and southern Asia, wintering in the tropics of Africa and Asia, with a ...

(''H. pennatus''),

little eagle The little eagle (''Hieraaetus morphnoides'') is a very small eagle endemic to Australia. Taxonomy John Gould Species description, described the little eagle in 1841. The distinctive pygmy eagle has long been considered a subspecies, but a 2009 ...

(''H. morphnoides'') and

Ayres's hawk-eagle Ayres's hawk-eagle (''Hieraaetus ayresii''), also referred to as Ayres' eagle,Newman, K (1998) Newman's Birds of Southern Africa. Halfway House: Southern Book Publishers. . is a medium-sized bird of prey in the family Accipitridae. It is native t ...

(''H. ayresii''), consists of much smaller species, that are in fact the smallest birds called eagles outside of the unrelated '' Spilornis'' serpent-eagle genus. This genus has recently been eliminated by some authorities and its members included in ''Aquila'', although not all ornithological unions have followed this suit in this re-classification. The small-bodied

Wahlberg's eagle Wahlberg's eagle (''Hieraaetus wahlbergi'') is a bird of prey that is native to sub-Saharan Africa, where it is a seasonal migrant in the woodlands and savannas. It is named after the Swedish naturalist Johan August Wahlberg. Like all eagles, it ...

(''H. wahlbergi'') has been traditionally considered an ''Aquila'' species due to its lack of change from juvenile to adult plumage and brownish color, but it is genetically aligned to the ''Hieraaetus'' lineage. Cassin's hawk-eagle (''H. africanus'') is also probably closely related to the ''Hieraaetus'' group rather than the ''Spizaetus/Nisaetus'' "hawk-eagle" group (in which it was previously classified) which is not known to have radiated to Africa.

Notes

References

{{Accipitriformes Eagles Bird common names