Golden Eagle Aquila chrysaetos Scientific name definitions

Todd E. Katzner, Michael N. Kochert, Karen Steenhof, Carol L. McIntyre, Erica H. Craig, and Tricia A. Miller
Version: 2.0 — Published September 17, 2020


Field Identification

A large, heavy-bodied, dark-brown, long-winged raptor (length 70–99 cm, wingspan 185–222 cm; male mass 2,387–4,500 g, female mass 3,048–6,460 g). Measurements and descriptions are from Clark and Wheeler (22), Watson (2), Lish et al. (23), and others as noted. Plumage changes with age. Adults (> 5 years old) are predominantly dark brown but have faint gray bars on the tail and golden, sometimes faded, feathers on the rear of the crown, the nape, and the sides of the neck. For birds older than ~1 year, the leading edge of the wing and upperwing coverts are generally paler than the rest of the feathers. The latter form light/tawny diagonal bars on the upper wing that are visible both on flying and perched eagles. Undertail coverts have been described in different ways, usually as brownish gold to dark rufous, and the feathered tarsi vary from white or light cream color to dark brown (24). The bill is tipped with black, fading to grayish near the base, and the cere is yellow. Sexes are similar in appearance, but females tend to be larger than males, and there may be sex-related differences in the pattern and number of tails bands of adults (see Appearance: Plumages: Definitive Basic Plumage; 25, 26, 2). Plumages are the same throughout the year, although fresh feathers are dark, shiny, and smooth on the edges. Differential fading occurs (27), with old feathers generally appearing faded, more brownish or even yellow white, and frayed on the edges (see Appearance: Molts). Occasionally, some individuals have small white “epaulets”, composed of a variable number of feathers at the upper end of the scapulars (28, 29); the trait appears to be uncommon, but widespread across North America (29), and may be referred to as the barthelemyi or Barthelemyi variant (30, 29, 31); see Appearance: Plumages.

Adult (> 4 yr) plumage differs from juvenile (0–1 yr) and subsequent subadult (1–3 yr) plumages (see Appearance: Plumages). Compared to adults and subadults, juveniles have a uniformly darker color when they first leave the nest. Unlike adults, juveniles usually have white at the proximal base of secondaries and inner primaries (32). These white areas form a white “window” at the carpal joint of the wing, visible in flight from above and below. Occasionally some upperwing coverts are also white (33). The amount of white on the wing varies among individuals, and some juveniles lack it altogether (22). The basal two-thirds of the tail of juveniles is usually white with a wide, dark band at the tip and a narrow white terminal band. Rectrices have some dark flecks, particularly near the dark band (24). The amount of white in the tail and wing varies but tends to diminish gradually with each progressive molt (see Appearance: Molts). However, some older individuals may retain white in the tail (24, EHC; T. Craig, personal communication). Adult plumage is usually acquired in the fifth summer. Physiological condition, stress, or damage to feathers can influence the rate and timing of molt of individual feathers and thus the appearance of the bird (24, 34, 35; see Appearance: Molts). It has recently been speculated that the bold contrasting plumage of young Golden Eagles may be a signal that these younger birds may be more aggressive, and thus willing to fight over a carcass meal (36).

Similar Species

Distinguished from most other raptors in North America by a combination of large size and mostly dark-brown color. The wings of Golden Eagle are longer and narrower than those of many smaller Buteo hawks. Similar in size and color to juvenile and subadult Bald Eagle (Haliaeetus leucocephalus) that have not acquired the distinctive adult white head and tail. The most striking differences involve distribution of white in the plumage and the size and shape of the head (37). Bald Eagle has a more elongated head profile, with a larger and more protruding head and bill, whereas Golden Eagle has a smaller head and bill (38, 39). When perched, Bald Eagle often holds its head feathers semi-erect, making the head appear more 'blocky' than that of Golden Eagle. Young Bald Eagle has a darker (blackish) bill and cere than Golden Eagle, which has a yellow cere. Bald Eagle juveniles and subadults have irregular patches of white or tawny coloration on their bodies, especially the underparts and under the wing (coverts, flight feathers, axillaries) and tail. Golden Eagle lacks extensive white on the body and the white on the wing and tail is not patchy. White on the undersurface of the wing in Golden Eagle is restricted to the base of flight feathers and white on the undersurface of the tail is sharply divided from the wide, dark, terminal band. Individual flight feathers of both species have white and brown patterns. However, the patterns on Golden Eagle are marbled, whereas feathers are spotted on Bald Eagle (40). Structural and behavioral differences are also useful in distinguishing these species. In flight, the head of a Golden Eagle does not project more than half the length of the tail, whereas the head of a Bald Eagle projects more than half the length of the tail (38, 41). In addition, the Golden Eagle has long outer secondaries that produce a noticeable round bulge, or shallow ‘S’ shape, on the trailing edge of the wing. The trailing edge of the wing is straighter for Bald Eagle. At close range, the Bald Eagle has naked tarsi, in contrast to the feathered tarsi of the Golden Eagle (22). Golden Eagle generally has shallower wing beats than Bald Eagle, and when soaring, does not hold its wings as flat as Bald Eagle (38, 39).

Soaring Golden Eagle could be confused with Turkey Vulture (Cathartes aura) , Black Vulture (Coragyps atratus), or California Condor (Gymnogyps californianus) . Turkey Vulture has a small head and is smaller overall; soars with a rocking motion and wings are held in a more pronounced dihedral; underwings are black in front and silver on the trailing edge. In contrast, Golden Eagle soars with wings in a much shallower dihedral and does not rock while soaring, except in very high winds (38, 41, TAM). Black Vulture has a very short tail, and the outermost primaries are all white. California Condor is larger than Golden Eagle but has a relatively short tail, a head that does not extend as far forward in flight, and unlike Golden Eagle, has an anterior white (adults) or white or mottled brown (pre-adult: any bird that has not attained adult plumage) underwing lining that forms a long narrow triangle (42).

For more information on identification in North America, see 22, 25, 38, 41, and 39. For more comparisons of Bald Eagle and Golden Eagle, especially individual feathers and bones, see 40 and 37.

In Eurasia and Africa, Golden Eagle can be confused with a wide variety of species. These include several other species of eagles in the genera Aquila, Clanga (formerly Hieraaetus), and Haliaeetus, as well as, other predatory raptors in the genus Buteo, Milvus, Pandion, Pernis, and Circaetus. Probably the most confusing species are Imperial Eagle (Aquila heliaca; 43), Steppe Eagle (A. nipalensis) , Greater Spotted Eagle (Clanga clanga) and Lesser Spotted Eagle (C. pomarina), and the many "brown" eagles of Africa (Wahlberg's Eagle [Hieraaetus wahlbergi], Tawny Eagle [Aquila rapax], Brown-Snake Eagle [Circaetus cinereus]) At a distance they may also be confused with vultures in the genera Gyps , Gypaetus, Neophron, and Aegypius. For details on identification in Europe, see Forsman (43). Confusion with other species is possible in Africa and Asia. In all regions, habitat associations may clarify identification, with the Golden Eagle more likely in mountainous terrain than Imperial or Steppe Eagles, and less likely around water than the Haliaeetus eagles.

Recommended Citation

Katzner, T. E., M. N. Kochert, K. Steenhof, C. L. McIntyre, E. H. Craig, and T. A. Miller (2020). Golden Eagle (Aquila chrysaetos), version 2.0. In Birds of the World (P. G. Rodewald and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.goleag.02