According to US Fish & Wildlife Service, bald eagles have been found to prey or take as carrion 46 species of birds, 20 species of mammals, 18 species of fish, 5 species of turtles, and 2 species of invertebrates.
On Decorah nest prey seen in the past has included, cottontail rabbit,muskrat,fox, squirrel, grey squirrel, coot, gosling, grebe, various other birds, fawn (likely road kill) piglet, raccoon, and fish including rainbow trout,redhorse sucker and white sucker.
That's why it is sometimes difficult to tell what has been brought in.