Alaska is the single most important location for bald eagles in North America, hosting the largest and most concentrated population in the United States. The presence of these large raptors is widespread across Alaska’s diverse geography, though their distribution is heavily influenced by the availability of food and suitable nesting habitat.
The Vast Population in Alaska
Alaska holds the overwhelming majority of the bald eagle population in the United States, with estimates suggesting the total number of birds is in the tens of thousands. The Alaska Department of Fish and Game estimates the population to be around 30,000 birds, including breeding adults, non-breeding “floaters,” and sub-adults, while other estimates range as high as 100,000 to 150,000 birds. This concentration is significantly higher than in the lower 48 states. This sheer number establishes a nesting density in Alaska that is the highest on the continent.
Prime Alaskan Habitats
The primary concentration of bald eagles in the state is found along the extensive coastline and offshore islands, particularly within Southeast Alaska. This panhandle region, characterized by a rugged, protected coastline and the massive Tongass National Forest, offers the ideal combination of abundant marine food sources and old-growth timber for nesting. The islands of Southeast Alaska exhibit the highest nesting densities observed anywhere for the species.
Eagles in this region prefer to build their massive nests in large, old-growth trees, such as Sitka spruce and Western hemlock. Nests are typically located near saltwater shorelines or mainland rivers, providing a clear view of the foraging area. Moving into Southcentral Alaska, the eagles often utilize old cottonwood trees near water sources for their nesting sites.
Chilkat Bald Eagle Preserve
One of the most famous examples of high-density habitat is the Alaska Chilkat Bald Eagle Preserve near Haines. This preserve, covering 48,000 acres, protects a vital river bottomland where a massive seasonal congregation occurs.
Seasonal Movements and Feeding Habits
Many bald eagles inhabiting the coastal regions of Southeast Alaska are considered year-round residents, while others exhibit seasonal movements. The eagles are opportunistic feeders, but their diet is overwhelmingly centered on fish, which is available in abundance along the coast and in interior rivers and lakes. Along the coast, they consume species like herring, pollock, and flounder, in addition to scavenging on carrion, small mammals, and various invertebrates.
The most dramatic seasonal behavior is the massive gathering that occurs annually in the Chilkat Valley. In the late fall and early winter, between 3,000 and 4,000 eagles congregate there to feed on a late run of spawning chum and coho salmon. This unique phenomenon is supported by warm water upwellings that keep a section of the Chilkat River ice-free, providing continuous access to the salmon carcasses.
Eagles generally begin their nesting activities in April. Pairs often rebuild and reuse the same nest each year, which can reach up to 10 feet across and four feet thick. The female typically lays two or three eggs, and the young will fledge and leave the nest after about 75 days.