This shield helps protect the eye from tree limbs and brush when the birds are in pursuit of dodging, feinting prey. It also shades the eye from the sun's glare and from damage due to struggling prey or clumsy feeding attempts by overzealous nestlings. Many raptors, like this red-tailed hawk, attack from a long, shallow dive so as not to alert their prey. In many of the Falconiformes, the female is larger than the male. The term tiercel denotes a male falcon.
Males often are that much smaller than their mates.
Indeed, in some species the female can be nearly twice as large. Most Falconiformes nest in relatively high, inaccessible locations in trees or on cliffs, though some, like the northern harrier, nest on the ground. Hawks and eagles build stick nests, while falcons dig a shallow scrape for their eggs on a cliff ledge, in a tree cavity or in a nest of another bird. Vultures lay their eggs on the ground inside a cave, log or tree. View from the ground Field observation of hawks is often just impressions of light and dark markings on the birds as they pass overhead.