The bald eagle is the national bird of the United States and the only eagle that lives exclusively in North America. (Golden eagles live in a broad swath across the northern hemisphere, including the United States.)
The bald eagle belongs to a larger group of eagle species called "sea eagles," because they are usually found near rivers or lakes, where they usually feed on fish. They will also take small mammals, such as rabbits, and will feed on carrion, such as deer killed by vehicles.
Bald eagles are often considered to mate for life, but this isn't completely true. While certain pairs remain together for many years, they will pair again if something happens to their mate. The pair may also winter in different areas and rejoin each other in early spring at their nesting site. Pair bonds may be partially or wholly dependent upon the quality of the territory.
Bald eagles establish breeding territories from which they exclude other eagles. One or more nests may be found within a territory, but only one is used. The nest is added to each year prior to nesting and adults may even carry greenery and additional sticks to the nest even when there are chicks present. Nests can grow to enormous sizes and weights.
Bald eagles are long-lived birds. Schempf reports a wild bald eagle living to 28 years of age and the Bird Banding Laboratory at Cornell University lists a record of a wild eagle living into its 30 year. Newton reported a captive eagle living to 36 years of age.
Bald eagle populations declined in the 19th and 20th centuries due to shooting and egg collecting. Their numbers began to rebound once they received protection through laws such as the Bald Eagle Protection Act of 1940, the Lacey Act, the Endangered Species Act, and two migratory bird treaties.
But just as their populations were recovering, the use of DDT, an insecticide that "bioaccummulates" in the food chain, caused egg shell thinning and bald eagle populations once more began to decline. When the United States and Canada banned DDT in the early 1970s, eagle populations recovered a second time.
The Mississippi National River and Recreation Area has approximately 22 active nests each year and the trend is for even more nests. Bald eagles may be seen throughout the Park, even in downtown areas along the river.
The Mississippi National River and Recreation Area and its partners conduct an annual eagle nest survey to better understand and mitigate the challenges faced by these birds.
As the eagle population grows along the river, however, they sometimes come into conflict with humans. For instance, they perch on airport antennae and pose threats to airplanes.
