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By Kari Kirschbaum
Geographic Range
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. (Kochert et al., 2002)
Other Geographic Terms:
holarctic 
.
Habitat
(11808 ft)
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. (Kochert et al., 2002)
These animals are found in the following types of habitat:
temperate ; polar ; terrestrial .
Wetlands: marsh .
Other:
suburban ; agricultural ; riparian ; estuarine .
Physical Description
(105.6 to 215.6 oz; avg. 160.6 oz)
(27.56 to 33.07 in)
(72.83 to 86.61 in)
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. (Kochert et al., 2002)
Some key physical features:
endothermic ; bilateral symmetry ; polymorphic .
Sexual dimorphism: female larger.
Reproduction
Golden eagles breed once yearly.
Golden eagles breed from March through August, depending on their geographic location.
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. (Kochert et al., 2002)
Mating systems:
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. (Kochert et al., 2002)
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous .
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. (Kochert et al., 2002)
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).
Lifespan/Longevity
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. (Kochert et al., 2002)
Behavior
Some populations of golden eagles are sedentary, while others are migratory. In North America, most golden eagles in Alaska and Canada travel south in autumn when the food supply on their northern range begins to decline. Most pairs that breed in the continental U.S. and southern Canada remain in the same area year-round.
Golden eagles are generally solitary or in pairs, though non-mated juveniles may be found in groups. Wintering adults may also be found in groups during times of extreme weather or very abundant food.
Golden eagles can carry up to 8 pounds during flight. They can fly up to 80 mph, though the average speed is 28-32 mph, and may reach speeds up to 200 mph in a dive. In flight, golden eagles hold their wings horizontal to the body, rather than at an angle as many other hawks and vultures do. They fly with slow, powerful wingbeats alternated with gliding and soaring. (Kochert et al., 2002)
Home Range
Golden eagle home range sizes vary with season and quality of habitat. During the breeding season, golden eagles in the western U.S. have home ranges from 20 to 33 square kilometers. Breeding pairs defend the boundaries of their home range with flight displays. (Kochert et al., 2002)
Key behaviors:
arboreal ; flies; diurnal ; motile ; migratory ; sedentary ; territorial ; dominance hierarchies .
Communication and Perception
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. (Kochert et al., 2002)
Food Habits
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. (Kochert et al., 2002)
Primary Diet:
carnivore (eats terrestrial vertebrates).
Animal Foods:
birds; mammals; reptiles; fish.
Predation
- wolverines (Gulo gulo)
- grizzly bears (Ursus arctos)
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. (Kochert et al., 2002)
Ecosystem Roles
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. (Kochert et al., 2002)
Economic Importance for Humans: Negative
Golden eagles occasionally kill livestock, costing ranchers money.
Economic Importance for Humans: Positive
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.
Ways that people benefit from these animals:
controls pest population.
Conservation Status
IUCN Red List: [link]:
Least Concern.
US Migratory Bird Act: [link]:
Protected.
US Federal List: [link]:
No special status.
CITES: [link]:
Appendix II.
State of Michigan List: [link]:
No special status.
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)
Other Comments
Golden eagles are sometimes called the American War Bird or the Bird of Jupiter (Terres, 1980).
For More Information
Find Aquila chrysaetos information at
Contributors
Kari Kirschbaum (author, editor), Animal Diversity Web Staff.
Alicia Ivory (author), University of Michigan.
