The Bald Eagle (Haliaeetus leucocephalus) of Alaska’s waterways and the
soaring Golden Eagle (Aquila chrysaetos) of the Interior are two of this state’s
most magnificent birds of prey. Long valued for their aesthetic beauty, eagles are
now recognized for their biological importance as scavengers and predators in
the natural environment. These raptors deserve our protection and respect.
General description: The Bald Eagle is so named for its conspicuous white
head and tail. The distinctive white adult plumage is not attained until 5 or more
years of age. Immature birds lack this easily identifiable characteristic and can
be confused with the Golden Eagle. The immature Bald Eagle’s unfeathered tarsi
(lower legs) and whitish wing linings on the forward part of the wings, can be
helpful distinctions where the two species coexist. The Bald Eagle is Alaska’s
largest resident bird of prey (the Steller’s Sea Eagle is larger) with a wing span
up to 7 1/2 feet (2.3 m) long and weights of 8 to 14 pounds (3.6-6.4 kg). Like
many raptors, females are larger than males.
Life history: Found only in North America, Bald Eagles are more abundant in
Alaska than anywhere else in the United States. The Alaska population has been
estimated to include 30,000 birds at the time of fledging. Bald Eagles are often
found along Alaska’s coast, offshore islands, and Interior lakes and rivers. The
highest nesting densities occur on the islands of Southeast Alaska. Most Bald
Eagles winter in southern Alaska, but some leave the state during cold months.
In the Chilkat Valley, over 3,000 birds may congregate in late fall and early
winter to feed on spawned-out salmon.
Reproduction and nesting: Bald Eagles often use and rebuild the same nest
each year. Nest trees are usually close to water, afford a clear view of the
surrounding area, and often provide sparse cover above the nest. In Southeast
Alaska, Bald Eagles usually nest in old-growth timber along saltwater shorelines
and mainland rivers. Eagles in Southcentral Alaska nest in old cottonwood trees
near water. Nest building begins in April, and both the male and female gather
nest material. In late April, two (sometimes three) dull white or creamy yellow
eggs are laid several days apart. Incubation lasts about 35 days. When the young
hatch, sibling rivalry is common and the weaker, usually the younger, chick is
killed or starved. The surviving young leave the nest after approximately 75
days. They do not attain adult plumage and breed until 4 or 5 years of age. After
the breeding season, Bald Eagles congregate where food is plentiful, and they
may continue to roost near the nest tree.
Reproductive success can be affected by pesticides in the eagles’ prey. Alaska
Bald Eagles seem to be reproductively healthy, but contaminants have
been recorded in Alaska fish populations and in Bald Eagles. A greater
threat to Alaska’s Bald Eagle population is destruction of their nesting
habitat and nest disturbances. Nest trees tend to be the largest in
the stand and are usually 400 years old. In treeless areas on the
Aleutians, nests are located on rock pinnacles, or they may be on
Food habits: Fish are the main diet of the Bald Eagle. Herring, flounder,
pollock, and salmon are taken along the coast, while the Interior populations
prey heavily upon salmon. Eagles also prey upon waterfowl, small mammals, sea
urchins, clams, crabs, and carrion.
Management protection: Claims by fox farmers and fishers of
eagle depredations caused the Alaska Territorial Legislature in 1917
to impose a bounty system on eagles. These claims were later found
to be mainly false, but over 100,000 eagles were killed before the
bounty was removed in 1953. With statehood in 1959, the Bald Eagle
in Alaska received federal protection under the Bald Eagle Protection
Act of 1940. This act made it illegal to kill or possess an eagle,
alive or dead, or to possess any part of an eagle, including feathers.
Bald Eagles were endangered or eliminated throughout most of the Lower
48 states as a result of habitat destruction, illegal shooting, pesticides,
and poisoning. Bald Eagle populations are recovering in many states
because of strong support for endangered species wildlife habitat.
Alaska’s populations remain healthy, but careful stewardship and conservation
of nesting habitat and salmon spawning streams as well as minimizing
human disturbance near nest sites is necessary in order to protect
Alaska's Bald Eagles from the potential harm caused by increasing
In 1972, the Alaska State Legislature established a stretch of the Chilkat River as critical bald eagle habitat to ensure protection of the large numbers found there in winter. In 1982, a portion of the surrounding area was established as the Alaska Chilkat Bald Eagle Preserve.
General description: The Golden Eagle is named for the golden buff-colored
feathers on the crown and nape of the neck. The adult body color is usually dark
brown, and the dark-tipped tail is either darkly barred or spotted. Adult plumage
is acquired over a three to four year period and involves a gradual reduction in
the amount of white coloration. Immature Golden Eagles have white wing
patches and white at the base of the tail. This bird has a wing span from 6-7 feet
(1.8-2.1 m) and weighs 8-12 pounds (3.6-5.4 kg). It may carry a weight up to 7
pounds, but prey averages around 2 pounds.
Golden Eagles are found in northern regions of the entire northern hemisphere.
In Alaska, the range extends as far north as the Brooks Range with a limited and
scattered distribution in Southeast and rare occurrences in the Aleutians or
Alaska Peninsula. Not all eagles migrate but most go south when food supplies
Reproduction and nesting: Time of courtship varies with elevation and
latitude. Golden Eagles arrive at Denali National Park in March and as late as
May in the Brooks Range. Egg laying takes place from late April through May.
Usually a clutch of two eggs is laid with 35 to 45 days needed for incubation. It
takes 90 to 100 days for the hatchlings to become independent of their parents.
Nests (eyries) as large as 10 feet across (3 m) and 4 feet (1.2 m) thick are usually
located on cliffs, but trees may be used. Overall fledging success is
approximately one eaglet per pair. Since mortality in juveniles can be as high as
75 percent, it could take one mating pair up to 10 years to produce two breeding
Food habits: The Golden Eagle feeds mainly on ground squirrels, hares, and
birds such as cranes, owls, and ptarmigans. While golden eagles are capable of
killing large game animals (i.e., Dall sheep lambs, etc.), few killings have been
observed. Eagles also feed on carrion.
Management and protection: Federal and state laws protecting the Bald Eagle
also apply to the Golden Eagle, making possession illegal. Chemical
contaminants are not presently affecting the Golden Eagle. Loss of undisturbed
habitat seems the most serious threat to maintaining healthy populations of
Golden Eagles. Increasing human disturbance of eagles and remote area
development pose similar problems for Golden Eagles as they do for Alaska's
Text: David W. Daum
Illustration: Katherine Hocker
Revised and reprinted 1994, website revisions 2003