A harrier is any of the several species of diurnal hawks sometimes placed in the subfamily Circinae of the bird of prey family Accipitridae. Harriers characteristically hunt by flying low over open ground, feeding on small mammals, reptiles, or birds. The young of the species are sometimes referred to as ring-tail harriers. They are distinctive with long wings, a long narrow tail, the slow and low flight over grasslands and skull peculiarities. The harriers are thought to have diversified with the expansion of grasslands and the emergence of C4 grasses about 6 to 8 million years ago during the Late Miocene and Pliocene.

Hawks are birds of prey of the family Accipitridae. They are very widely distributed and are found on all continents except Antarctica.The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks, and others. This subfamily are mainly woodland birds with short broad wings, long tails, and high visual acuity. They hunt by dashing suddenly from a concealed perch. In America, members of the Buteo group are also called hawks; this group is called buzzards in other parts of the world. Generally, buteos have broad wings and sturdy builds. They are relatively larger-winged and shorter-tailed than accipiters, and fly further distances in open areas. Buteos descend or pounce on their prey rather than hunting in a fast horizontal pursuit....