The
bald eagle (
Haliaeetus leucocephalus, from Greek
hali "sea",
aiētos "
eagle",
leuco "white",
cephalos "head") is a
bird of prey found in
North America. A
sea eagle, it has two known subspecies and forms a
species pair with the
white-tailed eagle (
Haliaeetus albicilla). Its range includes most of Canada and Alaska, all of the
contiguous United States, and northern Mexico. It is found near large bodies of open water with an abundant food supply and old-growth trees for nesting.
The bald eagle is an opportunistic feeder which subsists mainly on
fish, which it swoops down and snatches from the water with its talons. It builds the largest
nest of any North American bird and the largest tree nests ever recorded for any animal species, up to 4 m (13 ft) deep, 2.5 m (8.2 ft) wide, and 1
metric ton (1.1
short tons) in weight.
[2] Sexual maturity is attained at the age of four to five years.
Bald eagles are not actually
bald; the name derives from an older meaning of the word, "white headed". The adult is mainly brown with a white head and tail. The sexes are identical in
plumage, but females are about 25 percent larger than males. The
beak is large and hooked. The plumage of the immature is brown