Haliaeetus leucocephalus (Linnaeus, 1766)
Bald Eagle (English), Pygargue à tête blanche (French), Águila cabeza blanca (Castilian)
The Bald Eagle (Haliaeetus leucocephalus), the official emblem of the United States, belongs to a group of birds known as fish eagles, which includes one or more species in most of the world except for the American tropics. Bald Eagles are generally found close to water and often occur in rather dense concentrations in certain areas during the winter. They breed from Alaska and northern Canada south to Baja California, Sonora, Arizona, New Mexico, Texas, and the Gulf coast from southeastern Texas to the Florida Keys (breeding is very local in interior North America). Southern and coastal adults often do not migrate, but birds from the far northern interior migrate south in winter. Although they often feed on carrion, including dead fish washed up on shorelines, and may steal food captured by other birds such as Ospreys (Pandion haliaetus), Bald Eagles are also capable of capturing their own prey in shallow water or on land. Their diet is usually dominated by fish when it is available, but also includes birds, mammals, and a variety of other small animals. Bald Eagles generally do not breed until four or five years of age and may mate for life. The large stick nests (which are constructed by both sexes) may be re-used and enlarged year after year. The 2 eggs (range 1 to 3) are incubated by both parents for 34 to 36 days. First flight of young birds is typically at around 10 to 12 weeks. (Kaufman 1996; AOU 1998)
During the late 19th century and first two thirds of the 20th century, Bald Eagle populations seriously declined over most of their range. Although the species had received some earlier legal protection, in 1978 the Bald Eagle was listed under the U.S. Endangered Species Act as Endangered in most of the lower 48 states (and as Threatened in the remainder). During the subsequent quarter century, however, the number of Bald Eagles in the lower 48 increased 25-fold to around 10,000 nesting pairs. This recovery is generally attributed to the 1973 banning in the United States of the insecticide DDT (which impairs normal egg development in birds of prey), protection from shooting, improved water quality, habitat protection, and hacking programs to actively reintroduce Bald Eagles to areas from which they had disappeared. The sustained and substantial population increases led to the downlisting of the Bald Eagle's status in the lower 48 states from Endangered to Threatened in 1995 and then to its de-listing altogether in 2007.