 Red-tailed hawks are the most robust and powerful of the North American buteos, a name given the red-tailed hawk, red-shouldered hawk and broad-winged hawk from their genus name, Buteo. The breeding range is also the most extensive, and such widespread geographical distribution has produced much variation in the bird, both in plumage color and in size. Typical red-tails are the mid-western birds of my own studies. The upper-parts of adults are dark chocolate brown rather mottled with grayish-white; their underparts vary from nearly white to brown, with a broken band of brownish streaking on the upper breast and a heavier band across the abdomen. The undersurface of the wings shows dark-tipped feathers, and the tail is reddish brown with a narrow white tip and usually a dark sub-terminal band. Immature birds have upper-parts that are duller brown than the adults', and their underparts are whiter; their tails are dull brown crossed by six to ten dark bands, and the abdominal band is usually more distinct than in adults. Adult males run from 19 to 22 l/2 inches in length, with wingspreads Of 46 to 5o inches; females vary from 21 to 25 inches in length, with wingspreads Of 48 to 58 inches. Adult males average 36 to 40 ounces in weight; the females 48 to 56 ounces. Northeastern red-tails are slightly smaller, and Florida birds are smallest of all.
 In flight, the red-tail cannot come close to matching the explosive dash of a Cooper's hawk, or the sustained drive of a peregrine falcon, because it is not built for speed like the accipiters and falcons. The long, wide wings of the red-tail are designed for soaring, the characteristic manner of flight at which the buteos excel.
On calm days one seldom sees a red-tail aloft for any length of time, except during the hot summer days when the birds encounter thermals and are able to rise with little effort. Ten- to twenty-mile-an-hour winds induce soaring, enabling the birds to remain in the air for extended periods with relative ease.
 Although red-tails usually do most of their hunting from a lookout perch, they also hunt from the air on favorable days when the wind is good. A hunting red-tail is easy to spot and strongly resembles a hovering rough-legged hawk, when hunting the open fields. Immature red-tails indulge in this hovering flight more often, possibly because they do not weigh as much as the adults and are more easily borne aloft in the wind. Though capable of spotting a mouse at a much greater instance, they seldom bunt from higher than 100 feet because the prey does not remain exposed for more than a few seconds and the attack must be quick.
 Adults are often observed hunting on the wing along mountain ridges or other places where horizontal winds are deflected upward, creating updrafts. Here, the birds are able to bang motionless in the air with little more effort than when perching on a lookout post. Red-tails hunting from 400 feet or more above the ground are almost certainly on the lookout for larger prey, which, once spotted, cannot disappear so quickly as a mouse or shrew.
Since only about one out of ten red-tails lives long enough to acquire the bright red tail, it is naturally well-educated in the school of survival. Buteos learn very quickly that it is useless to pursue flying birds under most conditions, and by the time they are mature they have learned their capabilities and limitations.
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