There is a group of eagles designated as Hawk Eagles. Don’t understand what the criteria is for this.
Taxonomy of the Changeable Hawk Eagle
There are also Ornate, Mountain and African Hawk Eagles.
http://en.wikipedia.org/wiki/Ornate_Hawk-Eagle
http://en.wikipedia.org/wiki/Mountain_Hawk-Eagle
http://en.wikipedia.org/wiki/African_Hawk-Eagle
There is a variety of eagles called hawk-eagles. These links discuss the specific birds and their characteristic, but I can’t find a reference that identifies why a bird is designated a hawk-eagle vs an eagle.
Nomenclature is lost in the mists of time. Folksy observations?
They are all raptors aka birds of prey.
The Merlin is known colloquially as a pigeon hawk.
The American Kestrel is also called a sparrow hawk.
It’s a confusing subject. Look at the species, subspecies and genus labels of these more- than-60 eagles.
http://en.wikipedia.org/wiki/Eagle