The Bald eagle (Haliaeetus leucocephalus) is a magnificent bird of prey found in North America. It is found near large bodies of open water with an abundant food supply and old-growth trees for nesting. It builds the largest nest of any North American bird and the largest tree nests ever recorded for any animal species. In the late 20th century the Bald eagle was on the brink of extirpation in the contiguous United States, however, populations have since recovered, and the species was removed from the U.S. government's list of endangered species on July 12, 1995.
The Bald eagle is an easily identified species of bird. Its body and wings are dark browns in color while the head and tail are white. The legs and feet are bright yellow and the eyes are light yellow. The Bald eagle has sharp talons on its feet and large, hooked beaks. Males of this species are smaller than females. Young and sub-adults are brown in color with different degrees of white spots on the lower part of their bodies.
Bald eagles inhabit a large territory, stretching from northern Mexico to the USA and Canada, thus covering the major part of North America. These birds are partially migratory, depending on location. If their territory has access to open water, the birds remain there year-round, but if the body of water freezes during the winter, making it impossible to obtain food, they migrate to the south or to the coast. During the breeding season, Bald eagles occur in 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. They require old-growth and mature stands of coniferous or hardwood trees for perching, roosting, and nesting. They will also nest in mangrove swamps, pinelands, seasonally flooded flatwoods, hardwood swamps, and open prairies and pastureland with scattered tall trees. While wintering, Bald eagles tend to choose open habitats, such as prairies, meadows, or tundra, or open forests with regular carrion access.
Bald eagles usually lead a solitary life, gathering in groups during nesting season. They also congregate into large roosts of up to 400 birds and groups may also gather in areas with a sufficient amount of prey. Bald eagles are comparatively inactive during strong winds and in winters. As the breeding season comes, they vocalize and chase conspecifics, thus defending the territory. Bald eagles hunt by day alone or in groups flying along the streams, wading in the water, catching fish, and eating it right on the spot. The birds communicate with each other using weak staccato, chirping whistles, 'kleek kik ik ik ik', somewhat similar in cadence to a gull's call. The calls of young birds tend to be more harsh and shrill than those of adults
Bald eagles are carnivorous (piscivorous) and feed mainly on fish. Their diet includes also small species of birds, rabbits, reptiles, crabs, and amphibians. In addition, they can eat the eggs of other birds.
Bald eagles are monogamous, mating once in a lifetime or living together until one of the mates dies. Courtship displays, performed by the bald eagles, are impressive and spectacular. They also perform fight displays, where the birds swoop at one another. The pair conducts the nest and then, 1-3 months later, eggs are laid. The season of egg-laying is late winter to early spring when the female usually lays 2 eggs. Both the male and the female take part in the incubation of the eggs for 34-36 days. After the chicks are hatched, one of the parents is constantly with them for about 2 weeks. Then, at the age of 10-12 weeks, the chicks start flying but the parents keep on feeding and protecting them for another 2-3 months. Eaglets become reproductively mature and start to breed when they are between 4 and 5 years of age.
Despite the fact that the recovery of the population has been conducted, threats are still present. One of the threats is the loss of habitat because of the occupation of coastal areas and the drainage of wetlands by humans. On the other hand, illegal shooting, human disturbance, pollution, collisions with power lines and air vehicles are among notable threats to this species’ population. And finally, pollutants contain a serious threat of poisoning: DDT, for example, can cause thinning of eggshells and reproductive failure.
According to the All About Birds resource the total breeding population size of the Bald eagle is 250,000 individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are increasing.
Due to being top predators, Bald eagles play important role in the ecosystem. The decline of their population and following recovery had a huge impact on the organisms of their habitat. For instance, it has caused the decline of murres’ population in the area.