The Osprey look and behave alot like fish eagles but because they have specific physical characteristics and behaviors that are different from eagles they are classified in their own group. P. haliaetus carolinensis is the subspecies that is seen in Illinois.
Eagles and Osprey
The term eagle refers to a very diverse group of birds that do not fall into the other birds of prey groups. There are several types of eagles including fish eagles, snake eagles, harpy eagles, and true eagles. Eagles are very similar to the buteo family of raptors but are generally larger, with larger feet and a much heavier beak. They also rely much more on surprise to catch their prey rather then pursuit. The two eagles found in IL are the Bald Eagles, and the Goldend Eagle.