Golden eagles (Aquila chrysaetos) have a Holarctic distribution. They occur throughout Eurasia, in northern Africa, and in North America. In North America, golden eagles are found in the western half of the continent, from Alaska to central Mexico, with small numbers in eastern Canada and scattered pairs in the eastern United States.

Biogeographic Regions: nearctic (Native ); palearctic (Native ); ethiopian (Native )

Other Geographic Terms: holarctic

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDS: North America: mainly western and northern Alaska east through Northwest Territories to Labrador, south to northern Mexico, Texas, western Oklahoma, western Kansas; in East to New York, New England (rare). See Lee and Spofford (1990) for a review of nesting records from the central and southern Appalachians (most nesting records south of the Adirondacks are doubtful). Breeds also in the Palearctic. WINTERS: south-central Alaska, southern Canada south through breeding range, casually southward. In the U.S., most numerous in winter in the Rocky Mountain states, Great Basin, and western edge of the Great Plains (Root 1988). See Milsap and Vana (1984) for information on winter range in the eastern U.S. Accidental in Hawaii. Northernmost populations in Eurasia winter south to northern Africa (Sibley and Monroe 1990).

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

occurs (regularly, as a native taxon) in multiple nations

Golden eagles are North America's largest predatory bird. They are dark brown raptors with long, broad wings. Their length ranges from 70 to 84 cm, and their wingspan ranges from 185 to 220 cm. Males and females are similar in appearance, but females are much larger than males. Female weight ranges from 3940 to 6125 g whereas male weight ranges from 3000 to 4475 g. Adults are largely dark brown, except for a golden area near the crown, nape and sides of the neck and face. The tail is grayish brown. From below, the large flight feathers of the wings appear to be brownish gray, while the head, body and smaller feathers on the forepart of the open wings are blackish. The eyes of adults are dark brown. The bills and claws are black, while the cere and feet are yellow. The legs are feathered all the way down to the toes.

Juvenile golden eagles appear similar to adults, except for light patches on the tips of the wings, and a wide white band on the tail and a terminal band of black. This plumage is sometimes referred to as its "ringtail" plumage as a result of these bands. Juveniles attain adult plumage between ages 4 and 6 years.

There are 5 or 6 recognized subspecies of the golden eagle. These subspecies are differentiated by geographic distribution, size and coloration. Only one subspecies, Aquila chrysaetos canadensis is found in North America.

Range mass: 3000 to 6125 g.

Range length: 70 to 84 cm.

Range wingspan: 185 to 220 cm.

Other Physical Features: endothermic ; bilateral symmetry ; polymorphic

Sexual Dimorphism: female larger

Average basal metabolic rate: 4.9929 W.

Length: 102 cm

Weight: 4692 grams

Differs from bald eagle in lacking a white head in adults and in lacking white spotting on the underwing coverts in immatures.

• Terrestrial

Golden eagles are found in open and semi-open habitats from sea level to 3600 m elevation. Habitat types that they inhabit include tundra, shrublands, grasslands, woodland-brushlands, and coniferous forests. Most golden eagles are found in mountainous areas, but they also nest in wetland, riparian and estuarine habitats.

Range elevation: 0 to 3600 m.

Habitat Regions: temperate ; polar ; terrestrial

Terrestrial Biomes: tundra ; taiga ; savanna or grassland ; chaparral ; forest ; mountains

Wetlands: marsh

Other Habitat Features: suburban ; agricultural ; riparian ; estuarine

Comments: Generally open country, in prairies, arctic and alpine tundra, open wooded country, and barren areas, especially in hilly or mountainous regions.

Nests on rock ledge of cliff or in large tree (e.g., oak or eucalytus in California, white pine in eastern North America). Pair may have several alternate nests; may use same nest in consecutive years or shift to alternate nest used in different years.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Northernmost populations withdraw southward for winter (some individuals may remain in north); these migrants may migrate farther south than do birds from breeding populations to the south; returns to northern breeding areas in March-April. Tends to vacate hot deserts during summer. See Palmer (1988) for discussion of seasonal movements.

A juvenile from Denali National Park, Alaska, migrated through Yukon Territory and interior British Columbia to a wintering site in east-central Idaho; another juvenile migrated through the Yukon, Alberta, and Saskatchewan to northeastern Montana (Britten et al. 1995).

The diet of golden eagles is composed primarily of small mammals such as rabbits, hares, ground squirrels, prairie dogs, and marmots. They also eat birds, reptiles and fish in smaller numbers. Golden eagles occasionally capture large prey, including seals (Phocoidea), ungulates, coyotes and badgers. They have also been known to capture large flying birds such as geese or cranes. A pair of eagles will often hunt together; one chases the prey to exhaustion, and the other swoops down for the kill. Golden eagles rarely cache prey for later consumption.

Animal Foods: birds; mammals; reptiles; fish

Primary Diet: carnivore (Eats terrestrial vertebrates)

Comments: Feeds mainly on small mammals (e.g., rabbits, marmots, ground squirrels). May also eat insects, snakes, birds, juvenile ungulates, and carrion. Rarely attacks large, healthy mammals (e.g., pigs, sheep, deer) (Terres 1980). Can fast for days between feedings. Hunts while soaring or from perch (latter especially used by young). May hunt cooperatively. See Palmer 1988 for further details.

Golden eagles impact the local populations of the animals that they prey on. They may also compete with other species for prey and habitat. For example, golden eagles may compete with bald eagles, coyotes, California condors, and white-tailed eagles for prey items. They most likely also compete with common ravens, gyrfalcons, peregrine falcons, rough-legged hawks and other species for territories.

Golden eagles have few predators. There is no record of predation of golden eagle eggs, and few records of adult or nestling predation. Wolverines and grizzly bears are the only recorded predators of golden eagle nestlings.

Known Predators:

• wolverines (Gulo gulo)
• grizzly bears (Ursus arctos)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

10,000 to >1,000,000 individuals

Comments: North American population in the mid-1980s was estimated at about 70,000; perhaps about 20,000 breeding pairs occur in the western U.S. De Smet (1987 COSEWIC report) gave an estimate of 50,000-100,000 for North America. About 35,000 in the contiguous United States. Kirk et al. (1995) reported that the estimated number of breeding pairs in Canada was 1000-5000. Worldwide population estimate is not available.

Territory size in several areas of the western U.S. averaged 57-142 sq km (Palmer 1988).

Golden eagles are mostly silent, except during the breeding season. They use nine different calls to communicate. Most calls appear to be associated with food delivery to nestlings and begging by the nestlings.

Golden eagles don't appear to use vocalizations to mark their territory. Instead, they use an undulating flight to defend the boundaries of their territory.

Communication Channels: visual ; acoustic

Comments: Commonly forages in early morning and early evening.

The oldest known golden eagle lived to 46 years in captivity. In the wild, golden eagles have been known to live up to 32 years.

Range lifespan

Status: wild: 48 (high) years.

Range lifespan

Status: captivity: 46 (high) years.

Average lifespan

Status: wild: 340 months.

Golden eagles are monogamous, and may maintain pair bonds for several years. In non-migrant populations, pairs appear to stay together year round. For migratory golden eagles, pair formation and courtship begin when the eagles return to the breeding grounds, between February and mid-April. There is no information available regarding whether pair bonds are maintained year-round in migratory populations. Courtship activities in this species include undulating flight by one or both members of the pair, chases, dives, mock attacks, presenting talons, soaring together and circling.

Mating System: monogamous

Golden eagles breed from March through August, depending on their geographic location. Golden eagle pairs in much of the range are sedentary, remaining in the same territory year round. These pairs may begin nest-building and courtship as early as December. For migratory golden eagles, pair formation and courtship begin when the eagles return to the breeding grounds, between February and mid-April. Pairs may have several nests in their breeding territory and often re-use nests year after year, refurbishing them before each breeding season. Golden eagles usually build their nests on cliffs, but may also use trees, riverbanks and man-made structures, such as windmills, observation towers, nest platforms, and electrical towers. Nests are built 0 to 107 m off the ground. Both the male and female of a pair refurbish or build the nest, which may take 4 to 6 weeks. Nests are constructed of sticks and local vegetation and lined with soft vegetation, including shredded yucca, grasses, dry yucca leaves, inner bark, dead and green leaves, mosses and lichens. Nests may be huge if the site allows. The largest nest on record measured 6.1 m tall and 2.59 m wide.

The female lays 1 to 4 (usually 2) eggs, with 3 to 4 day intervals between each egg. The female begins incubating after the first egg is laid, and is responsible for most of the incubation, though the male often takes part. The eggs are dull white and spotted or blotched with brown or reddish brown. Incubation lasts for 35 to 45 days (average 42 days). The young hatch several days apart, and are altricial. The older nestlings are usually much larger than the younger nestlings, and the older, stronger eaglets often kill their smaller siblings. The chicks are brooded by the female with decreasing frequency for the first 45 days or so. Both parents bring food to the nestlings. The nestlings begin to leave the nest between 45 and 81 days of age by walking, hopping or falling out of the nest. They begin to fly around 10 weeks of age, and become independent from the parents 32 to 80 days after fledging. Juveniles do not breed until age 4 to 7 years, after attaining adult plumage.

Breeding interval: Golden eagles breed once yearly.

Breeding season: Golden eagles breed from March through August, depending on their geographic location.

Range eggs per season: 1 to 4.

Average eggs per season: 2.

Range time to hatching: 35 to 45 days.

Average time to hatching: 42 days.

Range fledging age: 45 to 81 days.

Range time to independence: 32 to 80 days.

Range age at sexual or reproductive maturity (female): 4 to 7 years.

Range age at sexual or reproductive maturity (male): 4 to 7 years.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)

Average eggs per season: 2.

Female golden eagles are primarily responsible for incubation, though males may do some of the incubation. The female also broods the chicks for much of the time in the first 45 days after hatching. Both parents bring food to the nest, though the male provides the majority of food, especially in the first few weeks after hatching.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)

Egg dates: by late April in northern Alaska; peak late February-March, California to Texas (but earlier nesting may yield young ready to fly as early as March 1 in Texas); late February-early March in Utah; March-April in northeastern U.S.; as early as May 1 in northern Alaska (later if snow persists). Clutch size is 1-3, rarely 4 (usually 2). Incubation about 43-45 days, mostly by female. Young can fly at 60-77 days (longer in far north than in south), cared for by parents for 30+ additional days; family unit sometimes may remain together several months. Typically first breeds in 4th or 5th year. Lifelong monogamy may be the rule, though some apparent exceptions have been recorded. Positive correlation between breeding success and jackrabbit number was reported in Idaho, Colorado, and Utah. Distance between active nests almost never less than 0.8 km. See Palmer (1988) for further details on reproduction.

The golden eagle is federally protected under the Bald Eagle Protection Act of 1962. In some parts, a decline of golden eagle populations has been recorded. Washington and Montana list it as a species of special concern; and Maine, New Hampshire and New York recognize it as an endangered species. But in other areas they are common and populations are presumably stable. (Tesky, 1994)

Previous to the Protection Act of 1962, some 20,000 golden eagles were killed, mostly from aircraft, because they were thought to prey on yound sheep and goats. But studies in towns where sheep are raised found no evidence to support such claims, as almost 70% of the eagle diet consisted of rabbits. Many golden eagles have been electrocuted in power lines, caught in steel traps set for coyotes and other animals, and poisoned by ranchers. Direct and indirect human-caused mortality, disturbance and elimination of prey by habitat alteration are the main factors limiting golden eagle populations. Recreational activites may also disturb breeding, migration and wintering activities. Golden eagles are likely to abandon nests during incubation if they are disturbed. (Terres, 1980;   http://www.fs.fed.us/database/feis/animals/Bird)

US Migratory Bird Act: protected

US Federal List: no special status

CITES: appendix ii

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Resident breeder and winter visitor?

Least Concern.

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

Rounded Global Status Rank: G5 - Secure

Reasons: Widespread distribution throughout the Northern Hemisphere. Still relatively common in some areas. Rank reflects primarily the extensive distribution; local threats/declines do not yet comprise a major conservation problem from a global perspective.

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: Declined in early 1900s due to eradication campaigns, frequently encouraged by the use of bounties (eagle was believed to be a major predator on livestock). Extremely susceptible to powerline electrocution because wings can span phase-to-phase or phase-to-ground wires (Biosystems Analysis 1989); modifications have been made in problem areas. Other threats include poison intended for coyotes, occasional shootings, and habitat loss to agriculture and suburban land uses. See De Smet (1987 COSEWIC report) for further discussion of threats. Small population in eastern North America may be negatively affected by poor survival to breeding age (Palmer 1988).

Management Requirements: Sensitive to disturbance in nesting area.

Relocation of breeding adult eagles (residents) offers, at best, only a short-term soluation to the problem of eagle predation on livestock (in Wyoming, most relocated birds reestablished their territories) (Phillips et al. 1991).

See Fala et al. (1985) for information on artificial nest sites.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: Protected in National Parks. Protected, by similarity of appearance, under the Bald Eagle Protection Act.

Needs: Protect both nesting sites and foraging areas/prey populations.

Golden eagles occasionally kill livestock, costing ranchers money.

Some researchers suggest that golden eagles are beneficial to livestock production because they eat a large number of rabbits, which compete with livestock for forage.

Positive Impacts: controls pest population

Comments: In many cases, resident eagles may be responsible for chronic loss of young domestic lambs, particularly in parts of Colorado, Wyoming, Montana, and Utah (see Phillips et al. 1991).

Eagle feathers are used for religious and cultural purposes by Native Americans, and the Department of the Interior is responsible for facilitating the distribution of eagle carcasses for these purposes (executive directive, 29 April 1994).