Eagles
Distribution
Golden Eagles are large birds of prey found in the
West and across Canada and Alaska. The birds are rare or irregular
visitors to the Midwest and Eastern states, although they were found
historically in eastern North America. The birds winter in North America
from south-central Alaska to central Mexico. Internationally, Golden
Eagles are found in Eurasia and northern Africa.
Description
Adult Golden Eagles are nearly alike except the
female is larger than the male. Their plumage is dark brown overall, with
some white at the base of the tail and golden-to-blond feathers on the
back of the head (the nape). Bill and talons are black; cere (soft
membrane that covers the nostrils) and feet are yellow. Immature birds
have a broad, white tail band with a black edge, and large white patches
on the undersides of the wings at the base of the primary feathers.
Sometimes a white line extends from this large patch toward the body. In
their second year, this white patch becomes smaller. Adults weigh 9 to12.5
pounds.
Habitats
Golden Eagles are birds of open country, not forests,
from desert grasslands to above timberline. They build large stick nests
in trees or cliff walls where they have plenty of room to
maneuver.
Flight
Golden Eagles are masters at soaring. With their
large wingspread -- 6.5 to7.5 feet --
these birds can
soar for long periods of time with little wing flapping. They may catch
thermals, rising masses of warm air, to carry them in a spiral fashion
upward high into the sky.
If the bird spots prey while soaring, it can
tuck its wings and swoop at speeds up to 200 mph. If you are close enough,
the bird may sound like a low-flying, small airplane. The birds may also
hunt from a favorite perch.
Golden Eagles use their tremendous eyesight
to locate prey. They prefer to attack upwind, to increase their
aerodynamic control and maneuverability. The birds prey upon a variety of
creatures from prairie dogs, cottontail rabbits, jackrabbits and ground
squirrels to grouse, ducks, chukars, reptiles and smaller birds. One study
that reviewed the list of Golden Eagle prey items in North America found
the birds preyed upon (depending upon their location) 52 species of
mammals, 48 birds, 5 reptiles and 2 fish. The birds will also feed on
carrion, which sometimes results in death from vehicle collisions or
poisoning.
Territories
Golden Eagles defend large breeding area home
ranges. Though their territories may be larger, they can not defend the
entire area continuously. Often, when an intruder enters an eagle's home
range, the bird will fly in a "roller coaster" flight, by soaring upward
to a point, then tucking its wings to descend. This pattern can be
repeated in a series; the undulating flight is truly inspiring to
watch.
Though nesting territories may be occupied
yearly, there are generally several nest sites in the area that are used
on different years. These nests may be over 0.5 miles apart. Alternate
nests range from 1 to 11 per territory.
Breeding
Nests are
constructed of large twigs or roots and can be lined with moss, bark, fur
or other soft material. The nest may become huge, as much as 8 to 10 feet
across and 3 to 4 feet deep.
Eggs are laid between February and May (or
May to June in the Arctic) commonly two per nest, although up to four eggs
could be laid in one clutch. Incubation time is 43 to 45 days. Usually,
the female does most of the incubating. Occasionally, depending upon food
resources, the older, stronger eaglet may kill its smaller nest mate
(siblicide).
The young will fledge when 72 to 84 days
old, and depend upon their parents for another 3 months. Then the young
will either migrate or move out of the parents' territory but overwinter
in their natal area.In winter, large groups of Golden Eagles may be
observed together.
Names
Golden Eagles get their name from their goldenish feathers on
the backs of their neck. Their scientific name, Aquila
chrysaetos (AK-qui-lah kris-AY-ee-tos), is from the Latin word
"aquila" meaning eagle, and from the Greek words "chrysos" meaning golden
and "aetos" meaning eagle.