Eagles, particularly the Bald Eagle, are powerful raptors found across North America. While some populations remain in their breeding territories year-round, many undertake seasonal movements to find suitable wintering grounds. This migration is primarily driven by changes in resource availability as colder temperatures set in, allowing them to access essential food sources and maintain energy balance.
Why Eagles Migrate
The primary reason eagles migrate during winter is food scarcity. Bald Eagles predominantly feed on fish, and when northern lakes and rivers freeze, this food source becomes inaccessible. This forces them to seek areas where open water persists, ensuring a continued fish supply.
Beyond fish, eagles also rely on waterfowl and carrion for sustenance, which can become limited in harsh winter conditions. They adapt their behavior, becoming more flexible in their diet and embracing a more communal lifestyle to survive. The search for adequate food compels northern populations to move south in late autumn and early winter.
Common Winter Destinations
Eagles disperse widely across the continental United States during winter, favoring locations with open water, abundant food, minimal human disturbance, and secure roosting sites. They are found along coastlines, large rivers, and lakes that remain unfrozen.
The Upper Mississippi River and its major tributaries are prime wintering grounds, with thousands of eagles congregating there. Waters below dams often remain ice-free, providing consistent access to fish. Areas like Red Wing and Wabasha in Minnesota are notable for their winter eagle populations.
Other important wintering areas include the Pacific Northwest, where hundreds gather along rivers like the Upper Skagit River watershed, drawn by salmon runs. The Klamath Basin on the California-Oregon border hosts one of the largest concentrations in the Lower 48 states, with up to 1,000 eagles present in January and February. Eagles also winter along the Atlantic Coast from Maine to Chesapeake Bay, and in parts of the West and Southwest, including Utah, and along major rivers and reservoirs in Oklahoma.
Life in Wintering Grounds
Upon reaching their wintering grounds, eagles adopt specific behaviors to conserve energy and find food. They often gather in large numbers at communal roost sites, typically in clusters of large trees that offer protection from wind and are close to food sources. These roosts, sometimes containing hundreds of birds, can serve a social purpose, potentially aiding in pair bonding and communication.
Eagles adapt their hunting strategies to winter conditions, frequently becoming more opportunistic scavengers than active hunters. They feed on carrion, such as roadkill, animals trapped in ice, or discarded carcasses, and will also exploit fish hatcheries or discarded bait from ice fishing.
When actively hunting, they may perch for extended periods to conserve energy, waiting for prey to become vulnerable, or utilize ice edges as hunting platforms to reduce flight expenditure. They can also strategically use wind to hover with minimal energy. They can go for several weeks without food if necessary, reducing activity levels and perching for hours to conserve energy.