Tuesday 17 September 2019

The Red-tailed Hawk Facts



Order Falconiformes, Family Accipitridae. The family Accipitridae includes most birds of prey except falcons, owls, and American vultures. Buteo hawks are moderately large soaring hawks that inhabit open or semi-open areas. They are the most common daytime avian predators on ground-dwelling vertebrates, particularly rodents and other small mammals.
They range in size from the broad-winged hawk (41 cm bill tip to tail tip) to the ferruginous hawk (58 cm). Hawks egest pellets that contain undigestible parts of their prey, such as hair and feathers, that can be useful in identifying the types of prey eaten (bones usually are digested completely).
Where Does Red-tailed Hawk Live?

The red-tailed hawk “Buteo jamaicensis” is the most common Buteo species in the United States. Breeding populations are distributed throughout most wooded and semi-wooded regions of the United States and Canada south of the tundra, although some populations are found in deserts and prairie habitats. Six subspecies are recognized. Nesting primarily in woodlands, red-tails feed in open country on a wide variety of small-to-medium-sized prey.
Body Size
Males of this medium-sized buteo (46 cm) weigh about 1 kg, and females are approximately 20 percent heavier than the males. Otherwise, the sexes look alike.
Habitat
Red-tails are found in habitats ranging from woodlands, wetlands, pastures, and prairies to deserts. They appear to prefer a mixed landscape containing old fields, wetlands, and pastures for foraging interspersed with groves of woodlands and bluffs and streamside trees for perching and nesting. Red-tails build their nests close to the tops of trees in low-density forests and often in trees that are on a slope.
In areas where trees are scarce, nests are built on other structures, occasionally in cactus, on rock pinnacles or ledges, or man-made structures. In winter, night roosts usually are in thick conifers if available and in other types of trees otherwise.
What Does Red-Tailed Hawk Eat?

The Red-tails hunt mainly from an elevated perch, often near woodland edges. Small mammals, including mice, shrews, voles, rabbits, and squirrels, are important prey, particularly during winter. Red-tails also eat a wide variety of foods depending on availability, including birds, lizards, snakes, and large insects.
In general, red-tails are opportunistic and will feed on whatever species are most abundant Winter food choices vary with snow cover; when small mammals such as voles become unavailable (under the snow), red-tails may concentrate on larger prey, such as pheasants.
Juvenile Red-tailed Hawk

Juveniles molt into adult plumage in a gradual process from the spring (age about 14 months) to summer or early fall.
Migration.
The more northerly red-tailed hawk populations are migratory while the more southerly is year-round residents.
Red-tailed Hawk Life Cycle

Red-tails lay one clutch per year consisting of one to three eggs, although a replacement clutch is possible if the initial clutch is lost early in the breeding season. Their nests are large and built of twigs. Both sexes incubate, but the male provides food for the female during incubation and the entire family following hatching. The parents continue to feed their young after fledging while they are learning to hunt.
Red-tailed Hawk Lifespan

The average life span of a wild red hawk is around 20 to 25 years.
Re-tailed Hawk Behavior
Red-tailed hawks are territorial throughout the year, including winter. Trees or other sites for nesting and perching are important requirements for breeding territories and can determine which habitats are used in an area.
Home range size can vary from a few hundred hectares to over 1,500 hectares, depending on the habitat. The size of red-tail territories and the location of boundaries between territories varied little from year to year, even though individual birds or pairs died and were replaced.
Population density.
Population densities normally do not exceed 0.03 pairs per hectare, and habitually are lower than 0.005 pairs per hectare. Populations in southern areas such as Florida can increase substantially in the winter with the influx of migrants from the more northerly populations.
Population dynamics.
Beginning at 2 years of age, most red-tailed hawks attempt to breed, although the proportion of breeding can vary by population and environmental conditions. Average clutch size varies regionally, tending to increase from east to west and from south to north. The density of their main prey, the snowshoe hare, over the years.
The mean clutch size for the red-tail population, however, appeared to vary with prey density, from 1.7 to 2.6 eggs/nest. Over the course of the study, about 50 percent of observed nestling losses occurred within 3 to 4 weeks after hatching due to starvation.
Most of the variance in yearly mortality of nestlings could be attributed to the amount of food supplied and the frequency of rain. Large raptors such as horned owls also can be important sources of mortality for red-tail nestlings in some areas.
Similar species
1.       The ferruginous hawk (Buteo regalis), one of the larger buteos (58 cm), inhabits the dry open country of the western United States.
2.       The red-shouldered hawk (Buteo lineatus) is slightly smaller (53 cm) and feeds on snakes, frogs, crayfish, mice, and some small birds. Its range is east of the Rocky Mountains and in California, with moist mixed woodlands preferred.
3.       Swainson's hawk (Buteo swainsoni) is restricted to the open plains of the western United States. Although it is as large (53 cm) as the red-tail, it preys mostly on insects.
4.       The broad-winged hawk (Buteo platypterus) is one of the smaller buteos (41 cm) and preys on mice, frogs, snakes, and insects. It prefers woodlands and is found almost exclusively east of the Mississippi River.
5.       Harris' hawk (Parabuteo unicinctus) is similar in size (53 cm) to the red-tailed hawk but is restricted to the semiarid wood and brushlands of the southwest. This bird nests in saguaro, mesquite, and yucca and preys on rodents, lizards, and small birds.
6.       The rough-legged hawk (Buteo lagopus) is one of the larger buteos (56 cm). It winters throughout most of the United States in open country but breeds only in the high arctic of North America.
7.       The zone-tailed hawk (Buteo albonotatus) is slightly smaller (51 cm) than most buteos and feeds on rodents, lizards, fish, frogs, and small birds. It can be found in mesa and mountain country within its limited range between the southwest United States and Mexico.














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