Editing Golden eagle (section)

== Description ==
===Size===
[[File:GoldenEagleFootLyd4.png|thumb|right|The foot and talons of a golden eagle]]
The golden eagle is a very large raptor, {{convert|66|to|102|cm|in}} in length. Its wings are broad and the wingspan is {{convert|1.8|to|2.34|m|ftin|0}}.<ref name="Cornell">{{cite web|url=http://www.allaboutbirds.org/guide/Golden_Eagle/lifehistory|title=Golden Eagle, Life History|year=2009|work=All About Birds|publisher=Cornell Lab of Ornithology|access-date=2010-12-26}}</ref><ref name= Ferguson-Lees>{{cite book|last1=Ferguson-Lees |first1=James |last2=Christie |first2=David A. |title=Raptors of the World |publisher=Houghton Mifflin Harcourt |year=2001 |isbn=0-618-12762-3}}</ref><ref>{{cite book|author=Peterson, Roger Tory |title=A Field Guide to Western Birds: A Completely New Guide to Field Marks of All Species Found in North America West of the 100th Meridian and North of Mexico|url=https://books.google.com/books?id=JCMEZ4EqzDIC&pg=PA180|year= 1998|publisher=Houghton Mifflin Harcourt|isbn=978-0-395-91174-7|pages=180–}}</ref><ref>{{cite book|title=National Geographic Field Guide To The Birds Of North America|edition=4th |year=2002 |publisher=National Geographic Society |isbn=978-0-79226-877-2}}</ref> The wingspan of golden eagles is the fifth largest among living eagle species.<ref name= Ferguson-Lees/> [[Sexual dimorphism|Females are larger than males]], with a bigger difference in larger subspecies. Females of the large Himalayan golden eagles are about 37% heavier than males and have nearly 9% longer wings, whereas in the smaller Japanese golden eagles, females are only 26% heavier with around 6% longer wings.<ref name= Watson/><ref name="Terres478"/> In the largest subspecies (''A. c. daphanea''), males and females weigh typically {{convert|4.05|and|6.35|kg|lb|abbr=on}}, respectively. In the smallest subspecies, ''A. c. japonica'', males weigh {{convert|2.5|kg|lb|abbr=on}} and females {{convert|3.25|kg|lb|abbr=on}}.<ref name= Watson/> In the species overall, males average around {{convert|3.6|kg|lb|abbr=on}} and females around {{convert|5.1|kg|lb|abbr=on}}.<ref name="HBW">{{cite book|title=Handbook of the Birds of the World |last1=del Hoyo |first1=J | last2=Elliot | first2 = A | last3=Sargatal | first3 = J | year=1996 |publisher=[[Lynx Edicions]] |location=[[Barcelona]] |isbn=84-87334-20-2|volume=3|title-link=Handbook of the Birds of the World}}</ref> The maximum size of golden eagles is debated. Large subspecies are the heaviest representatives of the genus ''[[Aquila (genus)|Aquila]]'' and this species is on average the seventh-heaviest living eagle species. The golden eagle is the second heaviest breeding eagle in North America, Europe and Africa and the fourth heaviest in Asia.<ref name="Brown"/><ref name= Ferguson-Lees/> For some time, the largest known mass authenticated for a wild female was the specimen from the ''A. c. chrysaetos'' subspecies which weighed around {{convert|6.7|kg|lb|abbr=on}} and spanned {{convert|2.55|m|ftin|abbr=on}} across the wings.<ref name = "Wood">{{cite book| author = Wood, Gerald | title = The Guinness Book of Animal Facts and Feats | year = 1983 | isbn = 978-0-85112-235-9 | url-access = registration | url = https://archive.org/details/guinnessbookofan00wood | publisher = Enfield, Middlesex : Guinness Superlatives}}</ref> American golden eagles are typically somewhat smaller than the large Eurasian species, but a massive female that was banded and released in 2006 around Wyoming's [[Bridger-Teton National Forest]] became the heaviest wild golden eagle on record, at {{convert|7.7|kg|lb|abbr=on}}.<ref name="Golden Eagle May Set Record">{{cite web|title=Golden Eagle May Set Record|url=http://newwest.net/main/article/largest_wild_golden_eagle_captured_in_jackson_hole/|publisher=Newwest|access-date=2015-06-26}}</ref>  Captive birds have been measured with a wingspan of {{convert|2.81|m|ftin|0|abbr=on}} and a mass of {{convert|12.1|kg|lb|abbr=on}}, though this mass was for an eagle bred for [[falconry]], which tend to be unnaturally heavy.<ref name = "Wood"/>

The standard measurements of the species include a [[Wing chord (biology)|wing chord]] length of {{convert|52|-|72|cm|in|abbr=on}}, a tail length of {{convert|26.5|-|38|cm|in|abbr=on}} and a [[Tarsus (skeleton)|tarsus]] length of {{convert|9.4|-|12.2|cm|in|abbr=on}}.<ref name= Ferguson-Lees/> The [[Culmen (bird)|culmen]] (upper ridge of beak) reportedly averages around {{convert|4.5|cm|in|abbr=on}}, with a range of {{convert|3.6|to|5|cm|in|abbr=on}}. The bill length from the [[gape]] measures around {{convert|6|cm|in|abbr=on}}.<ref>[http://www.gbgm-umc.org/grupongsagip/eagle.htm Sagip Eagle] {{webarchive|url=https://web.archive.org/web/20130928165222/http://www.gbgm-umc.org/grupongsagip/eagle.htm |date=28 September 2013}}. Gbgm-umc.org. Retrieved on 2012-08-22.</ref><ref>{{cite web|url=http://bna.birds.cornell.edu/bna/species/684/articles/measurements |title=Birds of North America Online—Birds of North America Online |publisher=Bna.birds.cornell.edu |access-date=2012-11-08}}</ref> The long, straight and powerful [[Claw|hallux-claw]] (hind claw) can range from {{convert|4.5|to|6.34|cm|in|abbr=on}}, about one centimetre longer than in a [[bald eagle]] and a little more than one centimetre less than a [[harpy eagle]].<ref name="Bortolotti">{{cite journal|author=Bortolotti, G.R. |title=Age and sex size variation in Golden Eagles |journal=Journal of Field Ornithology |volume=55 |issue=1 |pages=54–66 |year=1984 |jstor=4512857}}</ref><ref>{{cite journal |author1=Fowler, J.M. |author2=Cope, J.B. |title=Notes on the Harpy Eagle in British Guiana |journal=Auk |volume=81 |issue=3 |pages=257–273 |year=1964 |jstor=4082683 |doi=10.2307/4082683}}</ref><ref>{{cite web |url=http://www.learner.org/jnorth/tm/eagle/MaleVFemale.html |title=Journey North Bald Eagles |author=Nye, Peter |publisher=Journey North |access-date=2013-04-22 }}{{Dead link|date=March 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

===Colour===
[[File:Orel skalní 2.jpg|thumb|right|Subadult, showing white in tail and dark neck]]

Adults of both sexes have similar plumage and are primarily dark brown, with some grey on the inner wing and tail, and a paler, typically golden colour on the back of the crown and nape that gives the species its common name.<ref name=Clark/>  Unlike other ''Aquila'' species, where the [[Tarsus (skeleton)|tarsal]] feathers are typically similar in colour to the rest of the plumage, the tarsal feathers of golden eagles tend to be paler, ranging from light golden to white.<ref name= Watson/> In addition, some full-grown birds (especially in North America) have white "[[epaulettes]]" on the upper part of each scapular [[feather tract]].<ref name="Brown"/><ref name="Jollie">{{cite journal |last1=Jollie|first1=Malcolm|year=1947|title=Plumage Changes in the Golden Eagle|journal=Auk|volume=64|pages=549–576|publisher=American Ornithologists' Union|url=http://sora.unm.edu/sites/default/files/journals/auk/v064n04/p0549-p0576.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://sora.unm.edu/sites/default/files/journals/auk/v064n04/p0549-p0576.pdf |archive-date=2022-10-09 |url-status=live|access-date=2010-12-27 |doi=10.2307/4080715 |issue=4|jstor=4080715}}</ref> The bill is dark at the tip, fading to a lighter horn colour, with a yellow [[cere]].<ref>{{cite journal |last1=Clark|first1=William S|year=1983|title=The field identification of North American eagles|journal=North American Birds|volume=37|issue=5|pages=822–826|url=http://sora.unm.edu/sites/default/files/journals/nab/v037n05/p00822-p00826.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://sora.unm.edu/sites/default/files/journals/nab/v037n05/p00822-p00826.pdf |archive-date=2022-10-09 |url-status=live|access-date=2010-12-27}}</ref> As in many [[Accipitridae|accipitrids]], the bare portion of the feet is yellow.<ref name= Ferguson-Lees/> There are subtle differences in colouration among subspecies, described [[#Subspecies and distribution|below]].

Juvenile golden eagles are similar to adults but tend to be darker, appearing black on the back especially in [[East Asia]]. They have a less faded colour. Young birds are white for about two-thirds of their tail length, ending with a broad, black band.<ref name="Terres478"/> Occasionally, juvenile eagles have white patches on the [[remiges]] at the bases of the inner primaries and the outer secondaries, forming a crescent marking on the wings which tends to be divided by darker feathers.<ref name= Watson/><ref name=ABAaging>{{cite journal|last1=Liguori|first1=Jerry|year=2004|title=How to Age Golden Eagles|journal=Birding|pages=278–283|url=http://www.aba.org/birding/v36n3p278.pdf|access-date=2010-12-27|archive-url=https://web.archive.org/web/20120306212522/http://www.aba.org/birding/v36n3p278.pdf|archive-date=6 March 2012|url-status=dead|df=dmy-all}}</ref> Rarely, juvenile birds may have only traces of white on the tail. Compared to the relatively consistently white tail, the white patches on the wing are extremely variable; some juveniles have almost no white visible. Juveniles of less than 12 months of age tend to have the most white in their plumage.<ref name="Jollie" /> By their second summer, the white underwing coverts are usually replaced by a characteristic rusty brown colour. By the third summer, the upper-wing coverts are largely replaced by dark brown feathers, although not all feathers moult at once which leaves many juvenile birds with a grizzled pattern. The tail follows a similar pattern of maturation to the wings.<ref name="Jollie" /><ref name=ABAaging/> Due to the variability between individuals, juvenile eagles cannot be reliably aged by sight alone.<ref name= Juvenile>{{cite journal |author=Tjernberg, M. |title=Age determination of Golden Eagles, ''Aquila chrysaetos'' |journal=Vår Fågelvärld |volume=47 |pages=321–334 |year=1988 |issn=0042-2649}}</ref> Many golden eagles still have white on the tail during their first attempt at nesting.<ref>{{cite journal |author1=Ellis, D.H. |author2=Lish, J.W. |title=Thinking about feathers: adaptations of golden eagle rectrices |journal=Journal of Raptor Research |volume=40 |issue=1 |pages=1–28 |year=2006 |doi=10.3356/0892-1016(2006)40[1:TAFAOG]2.0.CO;2 |s2cid=86154133 |url=https://zenodo.org/record/1236457 |doi-access=free }}</ref> The final adult plumage is not fully attained until the birds are between {{frac|5|1|2}} and {{frac|6|1|2}} years old.<ref name= Juvenile/>

===Moulting===
[[File:GoldenEagle-Nova.jpg|thumb|Captive adult of the North American subspecies ''Aquila chrysaetos canadensis'']]
This species moults gradually beginning in March or April until September or October each year. Moulting usually decreases in winter. Moult of the contour feathers begins on the head and neck region and progresses along the feather tracts in a general front-to-back direction. Feathers on head, neck, back and scapulars may be replaced annually. With large feathers of the wing and tail, moult begins with the innermost feathers and proceeds outwards in a straightforward manner known as "descendant" moult.<ref name="Jollie" />

=== Vocalisations ===
[[File:Golden Eagle.jpg|thumb|right|Golden eagles are often silent.]] 
While many accipitrids are not known for their strong voices, golden eagles have a particular tendency for silence, even while breeding.<ref name= Leslie>{{cite book |last=Brown |first=L. |title=Eagles of the World |publisher=David and Charles |year=1976 |isbn=0360003184 }}</ref> That being said, some vocalization has been recorded, usually centering around the nesting period. The voice of the golden eagle is considered weak, high, and shrill, has been called "quite pathetic" and "puppy-like", and seems incongruous with the formidable size and nature of the species.<ref name= Ferguson-Lees/> Most known vocalisations seem to function as contact calls between eagles, sometimes adults to their offspring, occasionally territorial birds to intruders and rarely between a breeding pair. In western [[Montana]], nine distinct calls were noted: a ''chirp'', a {{Not a typo|''seeir''}}, a {{Not a typo|''pssa''}}, a {{Not a typo|''skonk''}}, a ''cluck'', a ''wonk'', a ''honk'' and a ''hiss''.<ref name= Ellis2/>

=== Flight ===
[[File:Golden Eagle in flight - 5.jpg|thumb|right|In flight]]

[[File:Golden Eagle flying.jpg|thumb|right|Golden eagle flying in dihedral with food]]
Golden eagles are sometimes considered the best fliers among eagles and perhaps among all raptorial birds.<ref name= Leslie/> They are equipped with broad, long wings with somewhat finger-like indentations on the tips of the wing.<ref name= Ferguson-Lees/> Golden eagles are unique among their genus in that they often fly in a slight [[Dihedral (aeronautics)|dihedral]], which means the wings are often held in a slight, upturned V-shape.<ref name= Ferguson-Lees/> When they need to flap, golden eagles appear at their most laboured, but this is less common than soaring or gliding––.<ref name= Watson/> Flapping flight usually consists of 6–8 deep wing-beats, interspersed with 2–3 second glides.<ref name= Watson/> While soaring, the wings and tail are held in one plane with the primary tips often spread.<ref name= SanDiego>{{cite web |url=http://library.sandiegozoo.org/factsheets/golden_eagle/golden_eagle.htm |title=Golden Eagle Fact Sheet |publisher=San Diego Zoo |access-date=2013-05-01 |archive-url=https://web.archive.org/web/20131012073405/http://library.sandiegozoo.org/factsheets/golden_eagle/golden_eagle.htm |archive-date=12 October 2013 |url-status=dead }}</ref> A typical, unhurried soaring speed in golden eagles is around {{convert|45|–|52|km/h|mph}}.<ref name="ADW">[http://animaldiversity.ummz.umich.edu/site/accounts/information/Aquila%20chrysaetos.html ADW: ''Aquila chrysaetos'': Information]. Animaldiversity.ummz.umich.edu. Retrieved on 2012-08-22.</ref> When hunting or displaying, the golden eagle can glide very fast, reaching speeds of up to {{convert|190|km/h|mph}}.<ref name= Watson/><ref name= SanDiego/> When stooping (diving) in the direction of prey or during territorial displays, the eagle holds its legs up against its tail, and holds its wings tight and partially closed against its body. When diving after prey, a golden eagle can reach {{convert|240|to|320|km/h|mph}}. Although less agile and manoeuvrable, the golden eagle is apparently quite the equal and possibly even the superior of the [[peregrine falcon]]'s stooping and gliding speeds.<ref name="Brown"/><ref>{{cite journal|author=Darling, F.F. |title=Speed of a Golden Eagle's flight |journal=Nature |volume=134 |issue=3383 |pages=325–6 |year=1934 |doi=10.1038/134325c0 |bibcode=1934Natur.134..325D |s2cid=4104511}}</ref> This makes the golden eagle one of the two fastest living animals.<ref name = "Wood"/> Although most flight in golden eagles has a clear purpose (e.g., territoriality, hunting), some flights, such as those by solitary birds or between well-established breeding pairs, seem to be play.<ref name="Brown" /><ref name= Leslie /><ref name= Palmer>{{cite book |author=Palmer, R.S. |chapter=Golden eagle: ''Aquila chrysaetos'' |title=Family Accipitridae (concluded) Buteos, Golden Eagle, Family Falconidae, Crested Caracara, Falcons |volume=5 |series=Handbook of North American birds |publisher=Yale University Press |year=1988 |isbn=0300040601 |pages=[https://archive.org/details/handbookofnortha0003palm/page/180 180–231] |chapter-url=https://archive.org/details/handbookofnortha0003palm/page/180 }}</ref>

=== Distinguishing from other species ===
[[File:Aquila chrysaetos Flickr.jpg|thumb|right|Golden eagles are readily distinguished by their brown plumage, paler than most other ''Aquila'', and pale nape patch.]]
Size readily distinguishes this species from most other raptors when it is seen well. Most other raptors are considerably smaller. ''[[Buteo]]'' hawks, which are perhaps most similar to the golden eagle in structure among the species outside of the "booted eagle" group, are often counted among the larger very common raptors. However, a mid-sized ''Buteo'' is dwarfed by a golden eagle, as an adult female eagle has about double the wingspan and about five times the weight. ''Buteos'' are also usually distinctly paler below, although some species occur in dark morphs which can be darker than a golden eagle.<ref name= Ferguson-Lees/><ref name= Cornell1>[http://bna.birds.cornell.edu/bna/species/684/articles/foodhabits Cornell University]. Bna.birds.cornell.edu. Retrieved on 2012-08-22.</ref> Among raptorial birds that share the golden eagle's range, only some [[Old World vulture]]s and the [[California condor]] are distinctly larger, with longer, broader wings, typically held more evenly in a slower, less forceful flight; they often have dramatically different colour patterns. In North America, the golden eagle may be confused with the [[turkey vulture]] from a great distance, as it is a large species that, like the golden eagle, often flies with a pronounced dihedral. The turkey vulture can be distinguished by its less controlled, forceful flying style (they frequently rock back and forth unsteadily in even moderate winds) and its smaller, thinner body, much smaller head and, at closer range, its slaty black-brown colour and silvery wing secondaries.<ref name= Dunne>{{cite book|year=1989|title=Hawks in Flight: The Flight Identification of North American Migrant Raptors|publisher=Houghton Mifflin Harcourt|location=Boston|isbn=0-3955-1022-8|author1=Sutton, C.|author2=Dunne, P.|author3=Sibley, D.|url-access=registration|url=https://archive.org/details/hawksinflight00clay}}</ref> Compared to ''[[Haliaeetus]]'' eagles, the golden eagle has wings that are only somewhat more slender but are more [[hawk]]-like and lack the flat, plank-like wing positioning seen in the other genus.<ref name= Dunne/> Large northern ''Haliaeetus'' species usually have a larger bill and larger head which protrudes more distinctly than a golden eagle's in flight. The tail of the golden eagle is longer on average than those of ''Haliaeetus'' eagles, appearing to be two or three times the length of the head in soaring flight, whereas in the other eagles the head is often more than twice the length of the tail.<ref name= Dunne/> Confusion is most likely between juvenile ''Haliaeetus'' and golden eagles, as the adult golden has a more solidly golden-brown coloration and all ''Haliaeetus'' eagles have obvious distinctive plumages as adults. ''Haliaeetus'' eagles are often heavily streaked in their juvenile phase. Juvenile golden eagles can have large patches of white on their wings and tail that are quite different from the random, sometimes large and splotchy-looking distribution of white typical of juvenile ''Haliaeetus''.<ref name= Ferguson-Lees/><ref name= Dunne/>

Distinguishing the golden eagle from other ''[[Aquila (genus)|Aquila]]'' eagles in Eurasia is more difficult. Identification may rely on the golden eagle's relatively long tail and patterns of white or grey on the wings and tail. Unlike golden eagles, other ''Aquila'' eagles do not generally fly in a pronounced dihedral. At close range, the golden to rufous nape-shawl of the golden eagle is distinctive from other ''Aquila''. Most other ''Aquila'' eagles have darker plumage, although the smaller [[tawny eagle]] is often paler than the golden eagle (the overlap in range is verified only in [[Bale Mountains]], [[Ethiopia]]). Among Eurasian ''Aquila'', the adult [[Eastern imperial eagle|eastern imperial]] and [[Spanish imperial eagle]] come closest to reaching the size of golden eagles, but both are distinguished by their longer necks, flatter wings in flight, white markings on their shoulder forewing-coverts, paler cream-straw coloured nape patch and generally darker colouration. Juvenile imperial eagles are much paler overall (caramel-cream in the Spanish; cream and tawny streaks in the eastern) and are not likely to be confused.<ref name= Ferguson-Lees/> [[Steppe eagle]]s can also approach golden eagles in size but are more compact and smaller headed with little colour variation to their dark earth-brown plumage, apart from juvenile birds which have distinctive cream-coloured bands running through their coverts and secondaries.<ref name="Brown"/> [[Verreaux's eagle]]s are most similar in size and body shape to the golden, the body of the Verreaux's eagle being slightly longer overall but marginally less heavy and long-winged than the golden eagle's.<ref name= Ferguson-Lees/> The plumage is very distinctly different, however, as Verreaux's eagles are almost entirely jet-black except for some striking, contrasting white on the wing primaries, shoulders and upper-wing.<ref name= Ferguson-Lees/> This closely related species is known to co-occur with the golden eagle only in the [[Bale Mountains]] of [[Ethiopia]].<ref name= Watson/> Other booted eagles in the golden eagle's range are unlikely to be confused due to differences in size and form. The only species in the genus ''Aquila'' that exceeds the golden eagle in average wingspan and length is the [[wedge-tailed eagle]] of [[Australasia]]; however, the wedge-tailed eagle is a slightly less heavy bird.<ref name = "Wood"/>