The Red-tailed Hawk is a medium-sized bird of prey, one of three species colloquially known in the United States as the "chickenhawk," though it rarely preys on chickens. It breeds throughout almost all North America from western Alaska and northern Canada to as far south as Panama and the West Indies, and is one of the most common buteos in North America. There are fourteen recognized subspecies, which vary in appearance and range. It is one of the largest members of the genus Buteo North America, typically weighing from 690 to 1600 grams (1.5 to 3.5 pounds) and measuring 45–65 cm (18 to 26 in) in length, with a wingspan from 110 to 145 cm (43 to 57 in). The Red-tailed Hawk displays sexual dimorphism in size, as females are about 25% heavier than males.
The Red-tailed Hawk occupies a wide range of habitats and altitudes, including deserts, grasslands, coniferous and deciduous forests, tropical rainforests, agricultural fields and urban areas. It lives throughout the North American continent, except in areas of unbroken forest or the high arctic. It is legally protected in Canada, Mexico and the United States by the Migratory Bird Treaty Act.
Because they are so common and easily trained as capable hunters, the majority of hawks captured for falconry in the United States are Red-tails. Falconers are permitted to take only hawks in their first year. Adults, which may be bred, are not permitted to be taken for falconry. Falconers prefer to train first year hawks, which have not been locked into uncooperative adult behaviors.
The Red-tailed Hawk also has significance in Native American culture. Its feathers are considered sacred by some tribes, and are used in religious ceremonies.
A male Red-tailed Hawk may weigh from 690 to 1300 grams (1.5 to 2.9 pounds) and measure 45–56 cm (18 to 22 in), while a female can weigh between 900 and 1460 grams (2 and 3.2 pounds) and measure Body size, 45 to 65 cm (18 to 26 in); Wingspan,is about 114 to 133 cm (45 to 52 in). As is the case with many raptors the Red-tailed Hawk displays sexual dimorphism in size, as females are 25% larger than males.
The western North American population, B. j. calurus, is the most variable subspecies and has three color morphs: light, dark, and intermediate or Rufus. The dark and intermediate morphs constitute 10–20% of the population.
Though the markings and hue vary, the basic appearance of the Red-tailed Hawk is consistent. The underbelly is lighter than the back and a dark brown band across the belly, formed by vertical streaks in feather patterning, is present in most color variations. The red tail, which gives this species its name, is uniformly brick-red above and pink below. The bill is short and dark, in the hooked shape characteristic of raptors. The cere, the legs, and the feet of the Red-tailed Hawk are all yellow.
Immature birds can be readily identified at close range by their yellowish irises. As the bird attains full maturity over the course of 3–4 years, the iris slowly darkens into a reddish-brown hue. In both the light and dark morphs, the tail of the immature Red-tailed Hawk are patterned with numerous darker bars.
The Red-Tailed Hawk is a member of the genus Buteo, a group of medium-sized raptors with robust bodies and broad wings. Members of this genus are known as buzzards in Europe, but hawks in North America.
There are at least 14 recognized subspecies of Buteo jamaicensis, which vary in range and in coloration:
The four island forms, jamaicensis, solitudinus, socorroensis, and fumosus, do not overlap in range with any other subspecies.
The Red-tailed Hawk is one of the most widely distributed hawks in the Americas. It breeds from central Alaska, the Yukon, and the Northwest Territories east to southern Quebec and the Maritime Provinces of Canada, and south to Florida, the West Indies, and Central America. The winter range stretches from southern Canada south throughout the remainder of the breeding range.
Its preferred habitat is mixed forest and field, with high bluffs or trees that may be used as perch sites. It occupies a wide range of habitats and altitudes, including deserts, grasslands, coniferous and deciduous woodlands, tropical rainforests, agricultural fields and urban areas. It is second only to the Peregrine Falcon in the use of diverse habitats in North America. It lives throughout the North American continent, except in areas of unbroken forest or the high Arctic.
The Red-tailed Hawk is widespread in North America, partially due to historic settlement patterns, which have benefited it. The clearing of forests in the Northeast created hunting areas, while the preservation of woodlots left nest sites. The planting of trees in the west allowed the Red-tailed Hawk to expand its range by creating nest sites where there had been none. The construction of highways with utility poles alongside treeless medians provided perfect habitat for perch-hunting. The Red-tailed Hawk can also be found in cities. The non-fiction book Red-Tails in Love: A Wildlife Drama in Central Park by Marie Winn made Pale Male, a Red-tailed Hawk in New York, the most famous urban Red-tailed Hawk.
In flight, this hawk soars with wings in a slight dihedral, flapping as little as possible to conserve energy. Active flight is slow and deliberate, with deep wing beats. In wind, it occasionally hovers on beating wings and remains stationary above the ground. When soaring or flapping its wings, it typically travels from 20 to 40mi/h, but when diving may exceed 120mi/h. When the Red-tailed Hawk walks, its steps are slow and awkward.
The Red-tailed Hawk is generally non-aggressive toward people and toward other birds. It is commonly harassed by crows, magpies, owls, other hawks, and even songbirds over territorial disputes, though it is generally not injured. When threatened by a human intruder, a Red-tailed Hawk will generally flee rather than defend its nest.
The cry of the Red-tailed Hawk is a two to three second hoarse, rasping scream, described as kree-eee-ar, which begins at a high pitch and slurs downward. This cry is often described as sounding similar to a steam whistle. It frequently vocalizes while hunting or soaring, but vocalizes loudest in annoyance or anger, in response to a predator or a rival hawk's intrusion into its territory. At close range, it makes a croaking "guh-runk". Young hawks may utter a wailing klee-uk food cry when parents leave the nest. 
Because of its robust crispness, a certain recording of the cry of the Red-tailed Hawk is a cliché cinematic sound effect. This high, piercing scream is often featured in the background of adventure movies to give a sense of wilderness to the scene. However, the cry is often inaccurately used for the Bald Eagle, whose own vocalizations are quite different and less robust.
The Red-tailed Hawk is carnivorous, and an opportunistic feeder. Its diet is mainly small mammals, but it also includes birds and reptiles. Prey varies with regional and seasonal availability, but usually centers on rodents. Additional prey (listed by descending likelihood of predation) include lagomorphs, shrews, bats, snakes, waterfowl, fish, crustaceans and insects.
The Red-tailed Hawk hunts primarily from an elevated perch site, swooping down from a perch to seize prey, catching birds while flying, or pursuing prey on the ground from a low flight.
Prey range in size from beetles to White-tailed Jackrabbits, which are double the weight of most Red-tails. In captivity in winter, an average Red-tail will eat about 135 g (4-5 oz) daily. The Great Horned Owl occupies a similar ecological niche nocturnally, taking similar prey. Competition may occur between the Red-tailed Hawk and the Great Horned Owl during twilight.
The Red-tailed Hawk reaches sexual maturity at two years of age. It is monogamous, mating with the same individual for many years. In general, the Red-tailed Hawk will only take a new mate when its original mate dies. The same nesting territory may be defended by the pair for years. During courtship, the male and female fly in wide circles while uttering shrill cries. The male performs aerial displays, diving steeply, and then climbing again. After repeating this display several times, he sometimes grasps her talons briefly with his own. Courtship flights can last 10 minutes or more. Copulation often follows courtship flight sequences, although copulation frequently occurs in the absence of courtship flights.
In copulation, the female, when perched, tilts forward, allowing the male to land with his feet lodged on her horizontal back. The female twists and moves her tail feathers to one side, while the mounted male twists his cloacal opening around the to the female's cloaca. Copulation lasts 5 to 10 seconds and during pre-nesting courtship in late winter or early spring can occur numerous times each day. In the same period, the pair constructs a stick nest in a large tree 4 to 21 m off the ground or on a cliff ledge 35 m (115 ft) or higher above the ground, or may nest on man-made structures. The nest is generally 71 to 97 cm (28 to 38 inches) in diameter and can be up to 90 cm (3 ft) tall. The nest is constructed of twigs, and lined with bark, pine needles, corn cobs, husks, stalks, aspen catkins, or other plant lining matter.
Great Horned Owls compete with the Red-tailed Hawk for nest sites. Each species has been known to kill the young and destroy the eggs of the other, but in general, both species nest in adjacent or confluent territories without conflict. Great Horned Owls are incapable of constructing nests and typically expropriate existing Red-tail nests. Great Horned Owls begin nesting behaviors much earlier than Red-tails, often as early as December. Red-tails are therefore adapted to constructing new nests when a previous year's nest has been overtaken by owls or otherwise lost. New nests are typically within a kilometer or less of the previous nest. Often, a new nest is only a few hundred meters or less from a previous one.
A clutch of 1 to 3 eggs is laid in March or April, depending upon latitude. Clutch size depends almost exclusively on the availability of prey for the adults. Eggs are laid approximately every other day. The eggs are usually about 60 x 47 mm (2.4 x 1.9 in). They are incubated primarily by female, with the male substituting when the female leaves to hunt or merely stretch her wings. The male brings most food to the female while she incubates. After 28 to 35 days, the eggs hatch over 2 to 4 days; the nestlings are altricial at hatching. The female broods them while the male provides most of the food to the female and the young, which are known as eyasses (pronounced "EYE-ess-ess"). The female feeds the eyasses after tearing the food into small pieces. After 42 to 46 days, the eyasses begin to leave the nest on short flights. The fledging period lasts up to 10 weeks, during which the young learn to fly and hunt.
The Red-tailed Hawk has a complex history with humans. The name "chickenhawk" was applied to the Red-tailed Hawk in earlier times, when free-ranging chickens and other domestic fowl were occasionally taken by these birds. First-year Red-tails, usually in late summer or early fall, were the most guilty of such predation. After mid-summer, adults seldom provide food for newly-hunting young Red-tails, and easily-captured, flightless chickens at a farmstead were frequent targets. Today, Red-tails and other hawks are universally protected by state, provincial, and federal bird protection laws.
The Red-tailed Hawk is a popular bird in falconry, particularly in America where the sport of falconry is tightly regulated at the federal and state levels. There are fewer than 4,000 falconers in the United States, therefore any effect on the Red-tailed Hawk population, estimated to be about one million in the United States, is statistically insignificant.
The Red-tailed Hawk is adaptable and useful in modern falconry. It is a powerful and sturdy falconry bird best flown at larger ground quarry such as squirrels, chicken, rabbits, and jackrabbits. Occasionally, the Red-tailed Hawk may even take a pigeon, crow, or duck.
In the course of a hunt, a falconer using a Red-tailed Hawk most commonly releases the hawk and allows it to perch in a tree or other high vantage point. The falconer, who may be aided by a dog, then attempts to flush prey by stirring up ground cover. A well-trained Red-tailed Hawk will follow the falconer and dog, realizing that their activities produce opportunities to catch game. Once a raptor catches game, it does not bring it back to the falconer. Instead, the falconer must locate the bird, "make in," and trade the bird its kill in exchange for a piece of ready-to-eat meat, which is generally from a previous kill.
The feathers and other parts of the Red-tailed Hawk are considered sacred to many American indigenous people and, like the feathers of the Bald Eagle and Golden Eagle, are sometimes used in religious ceremonies and found adorning the regalia of many Native Americans in the United States; these parts, most especially their distinctive tail feathers, are a popular item in the Native American community. As with the other two species, the feathers and parts of the Red-tailed Hawk are regulated by the eagle feather law, which governs the possession of feathers and parts of migratory birds.
. John Kenneth Terres. The Audubon Society Encyclopedia of North American Birds. Knopf. 1980. New York, NY. 1109. 0394466519.