The bald eagle, a majestic bird of prey, stands as the national symbol of the United States. Since its selection in 1782, this iconic raptor has come to represent strength and freedom, frequently depicted on various official U.S. items. These large birds are recognizable by their distinctive brown bodies and wings, contrasted with a striking white head and tail, complemented by a hooked yellow beak.
Geographic Distribution Across North America
Bald eagles are widely distributed across North America, from Mexico through the United States and Canada, reaching as far north as Alaska. While observed year-round in regions like Alaska, the East and West Coasts, the Rocky Mountains, and the Mississippi River, other parts of the continental U.S. primarily see them during winter and migration.
Historically, in the mid-1950s, their population was largely confined to Alaska, the Aleutian Islands, northern and eastern Canada, and Florida.
A significant recovery effort has allowed bald eagle populations to rebound and expand their observable range considerably. Once reduced to a low of only 417 known nesting pairs in the lower 48 states by 1963, their numbers have since grown dramatically. As of 2018-2019, the estimated population in the lower 48 states reached approximately 316,700 individuals, including 71,400 nesting pairs. This recovery has led to bald eagles nesting in every continental state and province across the United States and Canada.
Essential Habitat Requirements
Bald eagles require specific conditions to thrive. They are most often found near large bodies of open water, such as seacoasts, rivers, large lakes, and reservoirs. This proximity to water is important because fish are their primary food source, which they snatch from the surface.
Mature, tall trees, often coniferous or hardwood species, are also an important part of their habitat. These trees provide robust structures for nesting and elevated perches for hunting. Eagle nests, known as aeries, can become quite massive, sometimes reaching six feet across and six feet high, weighing over a ton. They also seek undisturbed areas, with ideal nest sites located 300 to 1,600 feet away from human activity. While fish are a staple, these opportunistic predators will also consume waterfowl, small mammals, and carrion when other food sources are scarce.
Seasonal Movements and Wintering Grounds
While bald eagles occupy a broad year-round range, many populations engage in seasonal movements, particularly those residing in northern areas. These migrations are primarily driven by the availability of open water and food sources. As northern lakes and rivers freeze in late autumn and early winter, eagles migrate southward to find accessible fishing grounds. In contrast, bald eagles in more temperate southern regions often remain resident in their breeding territories throughout the year.
During winter, bald eagles gather in significant concentrations at specific wintering grounds. These locations feature open water, abundant food, and protective roosting sites with limited human disturbance. Notable wintering areas include the Upper Mississippi River, the Chesapeake Bay, and the Klamath Basin along the California-Oregon border, which hosts the largest concentration in the lower 48 states. Other significant sites are along the Upper Skagit River in Washington, and parts of the Hudson and St. Lawrence Rivers.
Eagles often congregate at communal roost trees at night, sometimes traveling up to 32 miles from their feeding areas to these protected sites. Northern birds typically begin their return to breeding grounds in late winter, usually between January and March, once weather conditions permit and food becomes available.