It is one of the largest avian families – with 233 species in 67 genera recognized by the Howard and Moore Checklist of the Birds of the World. Twenty-four of these species occur in North America.
Several species occur in the tundra, others in alpine meadows and some in rainforests.
Breeding habits are diverse as well, some nest on cliffs, in trees and occasionally on the ground.
They feed on a wide range of prey items, which may include insects, small to medium-sized mammals, some may eat carrion (dead animals) – a few feed on fruit.
- Subfamily Elaninae – elanid kites (8 species)
- Subfamily Perninae – honey-buzzards (c.14 species)
- Subfamily Aegypiinae – Old World vultures
- Subfamily Gypaetinae
- Subfamily Buteoninae – buteonine hawks, true eagles and sea-eagles (c.100 living species, probably poly- or paraphyletic)
- Subfamily Circinae – harriers (some 16 living species)
- Subfamily Polyboroidinae – harrier hawks
- Subfamily Milvinae – milvine kites (some 14 species)
- Subfamily Accipitrinae – goshawks, sparrowhawks, and relatives (c.55 living species)
- Subfamily Circaetinae – snake-eagles (about one dozen species)
- Subfamily Harpiinae
- Subfamily Melieraxinae
- Subfamily Buteoninae – hawks (buzzards), true eagles and sea-eagles