Copyright Barbara Samuelson 1997
Bald eagle at the Alaska Raptor Rehabilitation Center,
Bald Eagle Facts:
What is the scientific name?
Pronounced hal-ih-ay-EE-tus lew-koh-SEFF-ah-lus
What does it mean? "White-headed sea eagle" Haliaeetus is a Greek
word meaning "sea eagle". Leucocephalus is Greek and is made up from
two other Greek words, leukos meaning "white" and kephale meaning "head."
In reference to the mature bald eagle's white head.
Why is it called the "Bald" eagle?
Odd that a bird with feathers all over its head has the name bald.
However, back in the year 1200 a language was spoken called Middle English.
The Middle English word balled meant "shining white" and was a reference
to the mature bald eagle's white head.
How big are they?
Females are larger, but both sexes are between 28 and 38 inches in
length and have a wingspread between 66 and 96 inches (up to eight feet!).
Females weigh between 10 and 14 pounds, males between 8 and 9 pounds.
How fast can they fly?
Between 36 and 44 miles per hour. One was clocked at 30 miles per
hour carrying a fish. Bald Eagles can reach speeds in excess of 100
miles per hour when diving.
How long do they live?
Uncertain. Between 80 to 90% of new born bald eagles die each year.
The oldest recorded living in the wild was 21 years, 11 months, however
Bald Eagles are believed to live 30 years or longer in the wild. In
captivity they have lived up to 48 years. They mate for life and build
huge nests in the tops of large trees near rivers, lakes, marshes, or
other wetland areas. Nests are often re-used year after year. With additions
to the nests made annually, some may reach 10 feet across and weigh
as much as 2,000 pounds. Although bald eagles may range over great distances,
they usually return to nest within 100 miles of where they were raised.
What do they eat?
Mainly fish, but also waterfowl, seabirds, mammals, and carrion.
The kind of fish it eats is dependent upon geographic location and what
is available. Species include salmon, eels, cod, herrings, carp, trout,
and catfish. Bird species include loons, ducks, cormorants, pelicans,
murrelets, terns, wild turkeys, ravens, flickers, and sparrows. Mammal
species include foxes, sea otters, rats, muskrats, porcupine, opossum,
skunk, prairie dogs, jackrabbits and squirrels. It has also been known
to attack domestic animals such as small pigs and dogs.
Bald Eagles build a large stick nest, sometimes weighing over 1 ton,
usually about 6 feet in diameter and over 6 six feet tall. The nests
are built near the tops of the largest trees near a river of lake. The
females lay from 1 to 3 eggs. Both males and females will incubate the
eggs. The young eagles hatch after 35 days and are ready to leave the
nest between 10 and 12 weeks of age.
Raptors form lasting pair bonds and are considered monogamous - which
means they have one mate. However, researchers are working to determine
whether it's actually the mate or the nest site that holds the strongest
loyalty. Both birds may be strongly bonded to a nest site where they
have had success in breeding, and, as a result, both birds return to
that site year after year and mate with each other. Each season the
pair bond is reestablished. If one of the pair dies, the other often
will take a new mate.
Wildlife experts believe there may have been 25,000 to as many as
75,000 nesting bald eagles in the lower 48 states when the bird was
adopted as our national symbol in 1782. Since that time, the bald eagle
has suffered from habitat destruction and degradation, illegal shooting,
and contamination of its food source, most notably due to the pesticide
DDT. By the early 1960s there were fewer than 450 bald eagle nesting
pairs in the lower 48 states.