Adult migrants tend to winter repeatedly in the same area, but remain mobile when seeking food during changing winter conditions. Winter night roosting occurs at sites where large numbers of eagles customarily congregate. Eagles usually begin arriving at the communal roost within the last two hours of daylight. They arrive as singles or as small disconnected groups sometimes travelling more than 10 miles from a feeding site. The first arrivals choose favorite trees and perches in the roost.
Much vocalization occurs as new birds arrive and vie for favored perching positions.
Before sunrise, eagles begin leaving the roost site for favorite feeding sites. Some communal roost sites in Nebraska are used by 100 to 200 bald eagles. Most people envision this majestic bird skimming along the surface of a lake or river and suddenly snatching an unsuspecting tish. Fish are the bald eagle's primary source of food, but the fish need not be alive to attract an eagle's attention. Winter die offs of shad or alewife at some of Nebraska's lakes and reservoirs provide readily available forage.