The falcons are small to medium sized birds with long, tapering wings built for speed. They feed on a variety of prey, from insects to birds. Although most falcons actively pursue their prey, the Kestrel is a familiar sight hovering along roadside verges waiting to pounce on an unlucky mouse or vole. In contrast, the Peregrine may reach speeds in excess of 100 mph in its bullet-like stoop for prey. The sexes are usually similar in plumage, but the female is generally larger in size. Unlike the hawks, to which they are closely related, they do not build nests, but use a scrape on a cliff ledge, or re-use an old nest built by someone else. In many species, nest-sites are traditional and may be used continuously for several decades.