Golden Eagle (Birds of Coronado NMem)

Golden Eagle

Aquila chrysaetos

Biology ⁶

Golden eagles hunt in a range of ways; they may soar and search for prey from on high, or sit in a tree on the look-out. They have also been seen flying low and then ambushing their prey. Food items taken include a range of small mammals including hares, rabbits, young foxes and rodents, as well as gamebirds and carrion (2). Pairs mate for life, and the huge nest (or 'eyrie') built in a tree or on a cliff-ledge will be used year after year providing it is not disturbed (2). Furthermore, these nests may be used by successive generations (6). Display flights occur during courtship in which the pair performs plunging and looping flights (6). Two eggs are laid following mating, and these are incubated for up to 45 days. The chicks fledge after 65-70 days. Golden eagles may live for as long as 32 years (6).

Migration ⁷

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.

Migratory populations may exist in areas where the species is present throughout the year, so specific migration patterns may be obscure. 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; migrants return to northern breeding areas mainly in March-April. Most vacate hot deserts during summer.

In predatory bird surveys over 12 months in the eastern Mohave Desert, San Bernardino County, California, Knight et al. (1999) observed golden eagles only during November and December, despite the species being a regular nesting bird in the Mohave Desert. The low number of observations may have reflected a naturally low density of eagles, lack of overlap of survey routes with eagle territories, or seasonal migrations of eagles between summer nesting areas in desert mountains and wintering areas in desert basins (Knight et al. 1999). 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).

Territory size in several areas of the western United States averaged 57-142 sq km (Palmer 1988). In desert regions, territories may be much larger (e.g., 258-310 sq km; see Wildlife Research Institute 2010).