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From Wikipedia, the free encyclopedia
The Red-tailed Hawk (Buteo jamaicensis) is a 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 most of 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. Red-tailed Hawks can acclimate to all the biomes within its range. There are fourteen recognized subspecies, which vary in appearance and range. It is one of the largest members of the genus Buteo in 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, with females averaging about 25% heavier than males.
The Harlan's Hawk (B. j. harlani), often considered a separate species, is treated below in the Taxonomy section.
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 passage hawks (which have left the nest, are on their own, but are less than a year old) so as to not affect the breeding population. Adults, which may be breeding or rearing chicks, may not be taken for falconry purposes and it is illegal to do so. Passage red-tailed hawks are also preferred by falconers because these younger birds have not yet developed adult behaviors, which can make training substantially more challenging.
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.
* 1 Description
* 2 Taxonomy
* 3 Distribution and habitat
* 4 Behavior
o 4.1 Flight
o 4.2 Vocalization
o 4.3 Diet
o 4.4 Reproduction
* 5 Relationship with humans
o 5.1 Use in falconry
o 5.2 Feathers and Native American use
* 6 References
* 7 External links
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 2000 grams (2 and 4.4 pounds) and measure 48 to 65 cm (19 to 26 in) long; 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 up to 25% larger than males.
Red-tailed Hawk plumage can be variable, depending on the subspecies and the region. These color variations are morphs, and are not related to molting. 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.They have short,broad tails and thick,chunky wings. 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:
* B. j. jamaicensis, the nominate subspecies, occurs in the northern West Indies, including Jamaica, Hispaniola, Puerto Rico and the Lesser Antilles but not the Bahamas or Cuba. El Yunque National Forest, Puerto Rico holds the highest known density of Red-tailed Hawks anywhere. 
* B. j. alascensis breeds (probably resident) from southeastern coastal Alaska to the Queen Charlotte Islands and Vancouver Island in British Columbia.
* B. j. borealis breeds from southeast Canada and Maine south through eastern Texas and east to northern Florida. It winters from southern Ontario east to southern Maine and south to the Gulf coast and Florida.
* B. j. calurus breeds from central interior Alaska, through western Canada south to Baja California. It winters from southwestern British Columbia southwest to Guatemala and northern Nicaragua. Paler individuals of northern Mexico may lack the dark wing marking.
* B. j. costaricensis is resident from Nicaragua to Panama. This subspecies is dark brown above with cinnamon flanks, wing linings and sides, and some birds have rufous underparts. The chest is much less heavily streaked than in northern migrants (B. j. calurus) to Central America.
* B. j. fuertesi breeds from northern Chihuahua to southern Texas. It winters in Arizona, New Mexico, and southern Louisiana. The belly is unstreaked or only lightly streaked, and the tail is pale.
* B. j. fumosus Islas Marías, Mexico
* B. j. hadropus Mexican Highlands
* B. j. harlani, Harlan's Hawk, is markedly different from all other Red-tails. In both color morphs, the plumage is blackish and white, lacking warm tones (save the tail). The tail may be reddish, dusky, whitish, or gray and can be longitudinally streaked, mottled, or barred. Shorter primaries result in wingtips that don't reach the tail in perched birds. It breeds in Alaska and northwestern Canada and winters from Nebraska and Kansas to Texas and northern Louisiana. This population may well be a separate species.
* B. j. kemsiesi is a dark subspecies resident from Chiapas to Nicaragua. The dark wing marking may not be distinct in paler birds.
* B. j. kriderii is paler than other Red-tails, especially on the head; the tail may be pinkish or white. In the breeding season, it occurs from southern Alberta, southern Saskatchewan, southern Manitoba, and extreme western Ontario south to south-central Montana, Wyoming, western Nebraska, and western Minnesota. In winter, it occurs from South Dakota and southern Minnesota south to Arizona, New Mexico, Texas and Louisiana.
* B. j. socorroensis Socorro Island, Mexico
* B. j. solitudinus Bahamas and Cuba
* B. j. umbrinus occurs year-round in peninsular Florida north to Tampa Bay and the Kissimmee Prairie. It is similar in appearance to calurus
The four island forms, jamaicensis, solitudinus, socorroensis, and fumosus, do not overlap in range with any other subspecies.
 Distribution and habitat
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, mountains, foothills of mountains 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.
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 40 mph (64 km/h), but when diving may exceed 120 mph (190 km/h).
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. The Red-tailed Hawk 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.
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, comprising up to 85% of a hawk's diet. Additional prey (listed by descending likelihood of predation) include lagomorphs, shrews, bats, snakes, waterfowl, fish, crustaceans and insects. 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 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.
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. Other competitors include other large buteos such as Swainson's Hawks and Rough-legged Hawks as well as the Northern Goshawk, since prey and foraging methods of these species occasionally overlap. Hawks have been observed following American Badgers to capture prey they flush and the two are considered potential competitors. Competition over carcasses may occur with American Crows and several crows working together can displace a hawk. Larger raptors, such as eagles and Ferruginous Hawks, may steal hawk kills.
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 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. Being a large predator, most predation of these hawks occurs with eggs and nestlings, which are taken by owls, corvids and raccoons.
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.
 Relationship with humans
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.
 Use in falconry
The Red-tailed Hawk is a popular bird in falconry, particularly in the United States where the sport of falconry is tightly regulated at the federal and state levels. There are fewer than 5,000 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.
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 and its captured prey, "make in," (carefully approach) and trade the bird its kill in exchange for a piece of offered meat.
 Feathers and Native American use
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.
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Da Wikipedia, l'enciclopedia libera.
Il falco coda rossa o poiana_codarossa(Buteo jamaicensis, J. F. Gmelin 1788) è un uccello rapace della famiglia degli accipitridae.