Nearly all eaters of live birds and mammals are in the hawk and owl families of birds. Raptors use their strong, hooked beaks and large talons to tear the flesh of fresh kills. Females are larger, with the plumage of the sexes nearly identical. Raptors have exceptionally acute eyesight. They have a much greater overlap of vision than do most birds, and five times the retinal cones of humans. There are two main types of raptors: Buteos and accipiters. Buteos locate prey by soaring or from a high perch. Accipiters catch birds in flight. Peregrine falcons stun birds in midair with clenched talons at speeds of up to 180 miles per hour. The falcon then catches the bird in mid-air. With their extremely strong talons, bald eagles can take animals many times their own body weight: The largest rodent species, raccoons, foxes, and weakened deer. Raptors have gotten a bad reputation as poultry killers, but studies have proven that the accused feed mainly on rodents tha, left unchecked, would damage crops. By taking the sickest and weakest animals, raptors improve genetic stocks. In the U.S., peregrines, balds, and osprey were adversely affected by the pesticide DDT, which interfered with the birds' hormone that produced calcium, resulting in too-fragile egg shells. Since a ban on DDT, the species have recovered dramatically.