The American kestrel hunts by hovering in the air with rapid wing beats or perching and scanning the ground for prey. Its diet typically consists of grasshoppers, lizards, mice, and small birds (e.g. sparrows).he American kestrel's scientific name, Falco sparverius, was given by Carolus Linnaeus in his 18th century work Systema Naturae. The genus refers to the falcate, or hooked, shape of the beak, and the specific name means pertaining to a sparrow, referring to the bird's small size and occasional hunting of sparrows.