For the most part, bald eagles prey on fish and waterfowl, so it stands to reason that you'll see them along waterways and lakes. In Montana, bald eagles tend to congregate and feed on salmon on the Missouri River below the dams—hundreds have been counted in one day. Fall is the best time of year to spot bald eagles as they migrate from Canada and Alaska to winter in Montana. Plan a trip for the fall of the year and bring your binoculars.
Immature bald eagles are difficult to identify because their plumage tends to vary, and the characteristic white head and tail aren't acquired until the bird is a full five years old. Bald eagles are the largest birds of prey; they're about three feet from head to tail with a wingspan of up to seven feet.