Bald eagle

The plumage of an adult bald eagle is evenly dark brown with a white head and tail. The tail is moderately long and slightly wedge-shaped. Males and females are identical in plumage coloration, but sexual dimorphism is evident in the species, in that females are 25% larger than males. The beak, feet and irises are bright yellow. The legs are feather-free, and the toes are short and powerful with large talons. The highly developed talon of the hind toe is used to pierce the vital areas of prey while it is held immobile by the front toes. The beak is large and hooked, with a yellow cere. The adult bald eagle is unmistakable in its native range.

The plumage of the immature is a dark brown overlaid with messy white streaking until the fifth (rarely fourth, very rarely third) year, when it reaches sexual maturity. Immature bald eagles are distinguishable from the golden eagle (Aquila chrysaetos), the only other very large, non-vulturine raptorial bird in North America, in that the former has a larger, more protruding head with a larger beak, straighter edged wings which are held flat (not slightly raised) and with a stiffer wing beat and feathers which do not completely cover the legs. When seen well, the golden eagle is distinctive in plumage with a more solid warm brown color than an immature bald eagle, with a reddish-golden patch to its nape and (in immature birds) a highly contrasting set of white squares on the wing.

Habitat

The bald eagle occurs during its breeding season in virtually any kind of American wetland habitat such as seacoasts, rivers, large lakes or marshes or other large bodies of open water with an abundance of fish. Studies have shown a preference for bodies of water with a circumference greater than 11 km (7 mi), and lakes with an area greater than 10 km2 (4 sq mi) are optimal for breeding bald eagles.

Behavior

The bald eagle is a powerful flier, and soars on thermal convection currents. It reaches speeds of 56–70 km/h (35–43 mph) when gliding and flapping, and about 48 km/h (30 mph) while carrying fish. Its dive speed is between 120–160 km/h (75–99 mph), though it seldom dives vertically. Regarding their flying abilities, despite being morphologically less well adapted to faster flight than golden eagles (especially during dives), the bald eagle is considered surprisingly maneuverable in flight. Bald eagles have also been recorded catching up to and then swooping under geese in flight, turning over and thrusting their talons into the other bird's breast.

Hunting

Their main diet consists of fish, particularly salmon, but they will also eat water birds, small mammals, snakes, carrion, and even human garbage. They regurgitate the indigestible parts of their food, including hair, feathers, and bone. In the winter they get most of their food by hunting ducks, searching for dead animals, and scavenging for fish during the fishes' spawning season.

Bald Eagles hunt by searching for their food from the air or from a perch, and are capable of seeing prey from a distance to up to one mile. They will swoop down to grab their prey, reaching speeds of up to 160 kph in a dive. They are able to swim by using their wings to paddle through the water and are known to chase after fish in shallow water with their beaks and talons. When hunting lagomorphs (rabbits and hares) they will hunt cooperatively with other eagles. Kleptoparsitism, stealing food from other animals, is common behavior.

Conservation status

Due to exposure to pesticides, such as DDT, which caused reproductive failure, along with other factors such as heavy metals in their diet and habitat loss, Bald Eagle populations sharply declined and the birds were declared endangered in the lower 48 states in 1967. They were upgraded to Threatened in 1995 and finally delisted in June, 2007. They are protected by the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act, which prohibits the take, transport, sale, trade, import, export, possession of, and possession of products of the two eagles.

Now, since they have a large range and population that appears to be increasing, Bald Eagles are listed as Least Concern by BirdLife International.