Red-tailed hawk

• 1. Introduction

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  The red-tailed hawk, Buteo jamaicensis, has a voice that millions of people know without ever seeing the bird. Television shows and other media often use its fierce, screaming cry as the stock sound of a raptor, even when the bird on screen belongs to another species.

  The real animal has a stranger and more adaptable story. One red-tail, known as Pale Male, became the subject of a nonfiction book, Red-Tails in Love: A Wildlife Drama in Central Park. That hawk was the first known red-tail in decades to nest successfully and raise young in the crowded New York City borough of Manhattan.

  How does a hawk end up raising a family beside the busiest streets in the country? What separates one red-tail from another across a whole continent? And why do falconers and indigenous communities alike treasure this bird?

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• 2. Names and Varieties

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  In 1788, the German naturalist Johann Friedrich Gmelin published the first scientific description of the bird and called it Falco jamaicensis. He built it on an earlier account by John Latham, who in 1781 wrote about a "cream-coloured buzzard" in A General Synopsis of Birds.

  Latham's bird was a specimen from Jamaica, sent to him by a friend. That island supplied the species name. Jamaica itself comes from the Taíno word Xaymaca, which means land of woods and water.

  The genus arrived eleven years after Gmelin's description. In 1799, the French naturalist Bernard Germain de Lacépède named it Buteo, from the Latin word for buzzard. The red-tail is one of 28 species in that genus, all medium-sized raptors with robust bodies and broad wings. Europeans call them buzzards, while North Americans call them hawks. The International Ornithologists' Union has designated red-tailed hawk as the official English name.

  In the United States, the bird is also one of three species colloquially called the chickenhawk. The label is unfair, since it rarely preys on adult chickens.

  At least 14 subspecies are recognized, and the strangest is Harlan's hawk, B. j. harlani. Its plumage is blackish and white in both color morphs, with no warm tones except in the tail. That tail may be reddish, dusky, whitish or gray, and it can be streaked, mottled or barred. Its primaries are shorter, so on a perched bird the wingtips do not reach the tail. It breeds in Alaska and northwestern Canada and winters from Nebraska and Kansas south to Texas and northern Louisiana. It is sometimes considered a separate species, B. harlani.

  Krider's hawk, B. j. kriderii, goes the opposite way. It is paler than other red-tails, especially on the head, and its tail may be pinkish or white. It breeds across the northern plains, from southern Alberta and southern Saskatchewan down to south-central Montana and western Nebraska.

  The western subspecies B. j. calurus breeds from central interior Alaska to Baja California and is the most variable of all. It comes in three color morphs, light, dark, and intermediate or rufous. The dark and intermediate forms make up 10-20% of the population.

  Farther south, B. j. costaricensis lives year-round from Nicaragua to Panama. It is dark brown above with cinnamon flanks, and some birds have rufous underparts. In Florida, B. j. umbrinus stays all year on the peninsula, north to Tampa Bay and the Kissimmee Prairie. Other island forms live on the Islas Marías and Socorro Island off Mexico, and in the Bahamas and Cuba.

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• 3. Size and Plumage

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  Researchers who weighed red-tailed hawks at migration sites and breeding grounds found that older reference weights ran about 15% too high. Nine studies at migration sites in the United States and two breeding studies, one in Puerto Rico and one in Wisconsin, put the average male at 837 g and the average female at 1040.7 g.

  Individual weights still span a wide range. Males may weigh from 690 to 1300 g and females from 900 to 2000 g, and part of that spread changes with the season. The heaviest surveyed group was made up of migrants at Cape May, New Jersey, where females averaged 1278 g and males 990.8 g. The lightest were breeding birds in forest openings in Puerto Rico, where females averaged 1023 g and males 795 g. That island population also shows the largest size gap between the sexes in the species.

  For all that, the red-tail is a steady performer. The heaviest race of great horned owl is about 36% heavier than the lightest race. The heaviest red-tail race is only just over 18% heavier than its lightest.

  Males measure 45 to 60 cm in total length and females 48 to 65 cm. Wingspan runs from 105 to 141 cm. The tail is 188 to 258.7 mm long. The talon on the rear toe, called the hallux claw, measures 24.1 to 33.6 mm and is the largest of any accipitrid, the hawk family.

  Most adults are easy to pick out by a red tail that ends in a single black band. Above, the tail is a uniform brick-red, and below it is a light buff-orange. The body is blocky and broad, usually heavier than other Buteo hawks of similar length. A whitish underbelly is crossed by a dark brown band of horizontal streaks. The bill is short, dark and hooked, the head can look small against the thick frame, and the cere, legs and feet are yellow.

  Young birds are harder to identify. Their tails carry about six darker bars, and their undersides may be covered in dark brown spotting. At close range, a yellowish iris is the clearest sign of youth, and it slowly darkens to reddish-brown as the bird reaches full maturity over 3-4 years.

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• 4. A Continental Range

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  In the Northeast, the clearing of forests opened up new hunting ground for red-tailed hawks, while preserved woodlots left them places to nest. Settlement patterns in North America, in other words, quietly favored the species.

  On the Great Plains, trees multiplied over the past century because of fire suppression and tree planting. That spread helped the red-tail expand westward, along with many other birds. Highways added utility poles beside treeless medians, which made ideal perches for hunting.

  Today the species breeds from central Alaska, the Yukon and the Northwest Territories east to southern Quebec and the Maritime Provinces of Canada. Its breeding range runs south to Florida, the West Indies and Central America. In winter it spreads from southern Canada throughout the rest of that range.

  The preferred setting is mixed forest and field, with high bluffs or trees to use as perches. Yet the bird also occupies deserts, grasslands, coastal regions, mountains, foothills, coniferous and deciduous woodlands, tropical rainforests, farm fields and cities. Only the peregrine falcon uses a more diverse set of habitats in North America. The exceptions are areas of unbroken forest and the high Arctic.

  Rock pigeons and brown rats can support red-tail populations in cities, where the hawk seems unfazed by considerable human activity. Adult hawks have few natural predators, though a variety of animals eat their eggs and chicks.

  Warfarin cookies are the bait that most often endangers urban red-tails. Used to kill rats and mice, they cause internal bleeding. A hawk that eats a poisoned rodent can be affected too.

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• 5. Voice and Hunt

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  Kree-eee-ar is the way the red-tail's cry is usually written down. The hoarse, rasping scream lasts two to three seconds, begins at a high pitch and slurs downward, and is often compared to a steam whistle. The hawk calls while hunting or soaring, but it is loudest when annoyed or angry, as when a predator or a rival hawk enters its territory. At close range it makes a croaking guh-runk. Young hawks give a wailing klee-uk food cry when their parents leave the nest.

  Rodents make up as much as 85% of the diet. Mice are the commonest prey, both native Peromyscus species and house mice, followed by gophers, voles, chipmunks, ground squirrels and tree squirrels. In descending likelihood come lagomorphs, shrews, bats, pigeons, quail, corvids, waterfowl, other raptors, reptiles, fish, crustaceans, insects and earthworms.

  On Caribbean islands, red-tails hunt mostly reptiles such as snakes and lizards, the most prominent native land animals there. The size range of prey is enormous. It runs from beetles and worms up to marmots, white-tailed jackrabbits and female wild turkeys, all at least double the weight of most red-tails. Carrion is eaten if need be but is not preferred. In winter, a captive red-tail eats about 135 g a day.

  Two hunting methods dominate. Often the hawk scans for movement from an elevated perch and swoops down to seize its prey. Otherwise it watches while flying, either catching a bird in the air or chasing ground prey until it can pin it with its talons.

  Some red-tails hunt in pairs. One tactic is to stalk opposite sides of a tree to surround a tree squirrel, so that one hawk flushes the animal into the talons of the other. Conspicuous meals also draw them in, such as displaying male red-winged blackbirds.

  The great horned owl works similar ground by night and takes similar prey. The two may compete at twilight, but their different nesting seasons and activity times usually prevent direct conflict. The red-tail's prey is on average larger, partly because diurnal squirrels are scarce in the owl's diet. Even so, the owl occasionally kills red-tails of any age, while hawks are not known to prey on adult great horned owls.

  Swainson's hawks, rough-legged hawks and the northern goshawk sometimes overlap with the red-tail in prey and methods. Red-tails have been seen following American badgers to catch the animals that the badgers flush. Over a carcass, several American crows working together can displace a hawk. Larger raptors, such as eagles and ferruginous hawks, may steal a red-tail's kill outright.

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• 6. Pair and Nest

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  Courtship flights can last 10 minutes or more. The male and female fly in wide circles while uttering shrill cries, and the male dives steeply, then climbs again. After repeating the display several times, he sometimes grasps her talons briefly with his own.

  Red-tails reach sexual maturity at two years of age. They are monogamous and mate with the same partner for many years, taking a new mate generally only when the original one dies. A pair may defend the same nesting territory for years. In late winter or early spring, copulation lasts 5 to 10 seconds and can occur numerous times each day.

  The pair builds a stick nest in a large tree 4 to 21 m above the ground. Alternatives are a cliff ledge 35 m or higher, or a man-made structure. The nest is generally 71 to 97 cm across and can stand up to 90 cm tall. Twigs form the frame, lined with bark, pine needles, corn cobs, husks, stalks, aspen catkins or other plant matter.

  Great horned owls cannot build nests of their own and typically seize existing red-tail nests. They also start nesting much earlier, often as early as December. Each species has been known to kill the young and destroy the eggs of the other. In general, though, the two nest in adjacent territories without conflict. Red-tails are adapted to building a fresh nest when an old one is taken, usually within a kilometer of the previous site and often only a few hundred meters away.

  Owls, corvids and raccoons take most of the eggs and nestlings that are lost to predators. A clutch of one to five eggs is laid in spring, roughly one egg every second day, and both parents incubate. The nestlings emerge over 2 to 4 days. The female broods them while the male provides most of the food to her, and she tears it into manageable pieces for the young.

  After 42 to 46 days, the young begin to leave the nest. Fledging, including learning to fly and hunt, takes about 10 weeks. The young begin to capture their own prey about 6 to 7 weeks after fledging.

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• 7. Wings and Winds

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  A dihedral is the slight upward tilt of the wings that a soaring red-tail often holds, and it flaps as little as possible to save energy. Active flight is slow and deliberate, with deep wing beats. In wind, the hawk occasionally hovers on beating wings and stays stationary above the ground. It typically travels at 32 to 64 km/h, but a dive can exceed 190 km/h.

  In most of Canada and Alaska, red-tails almost entirely vacate their breeding grounds, which makes the species a partial migrant. Coastal birds in the north, from the Pacific Northwest to southern Alaska and in Nova Scotia on the Atlantic, do not usually migrate. Wintering birds tend to be territorial but may shift ranges whenever food demands it.

  Autumn hawk watches in Ontario, Quebec and the northern United States have counted between 4,500 and 8,900 red-tails passing through. At Hawk Ridge in Duluth, Minnesota, records reach up to 15,000 in a season.

  Unlike Swainson's hawks and broad-winged hawks, red-tails do not usually migrate in groups. They pass one by one, and only on days when winds are favorable. Most do not travel beyond southern Mexico in late autumn. The northward movement can begin as early as late February and peaks in late March and early April. At the Derby Hill hawk watch in Oswego, New York, seasonal spring counts can reach 19,000 red-tails, and more than 5,000 have been recorded in a single day.

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• 8. Falconry and Feathers

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  Fewer than 5,000 falconers live in the United States, while the American red-tail population is estimated at about one million. Falconry's effect on the species is therefore negligible, even though most hawks captured for the sport are red-tails.

  The bird is popular because falconry is tightly regulated in the United States, and red-tails are both widely available and allowed to novices. They are highly tameable and trainable, with a more social disposition than any other falcon or hawk except Harris's hawk. They are also long-lived and highly disease-resistant, so a falconer can keep one as a hunting companion for many years.

  A red-tail is not as swift as a falcon or an accipiter, so it is usually flown at ground game such as rabbits and squirrels. Some individuals learn to ambush birds on the ground with a swift, surprise approach. A few have even learned a falcon-like diving stoop to take challenging game such as pheasants.

  In a typical hunt, the falconer releases the hawk to perch in a tree or other high point. The falconer, sometimes aided by a dog, stirs up ground cover to flush prey. A well-trained hawk learns to follow, realizing that the activity produces chances to catch game. A raptor does not bring its catch back. The falconer must find the bird, make in by approaching carefully, and trade the kill for a piece of offered meat.

  To many American indigenous people, the feathers and other parts of the red-tail are sacred. Like the feathers of the bald eagle and golden eagle, they are sometimes used in religious ceremonies and appear on the regalia of many Native Americans. The distinctive tail feathers are especially popular in the Native American community.

  The bird itself is legally protected in Canada, Mexico and the United States by the Migratory Bird Treaty. Its feathers and parts fall under the eagle feather law, the same rule that governs possession of feathers and parts of other migratory birds.

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