Red-tailed hawks average 48 to 65 centimeters in length. Their wingspan is approximately 4 feet, or 122 centimeters. There is sexual dimorphism in size: females are 25% larger than males. This kind of sexual dimorphism, where females are larger than males, is common in birds of prey.
Red-tailed hawk plumage ranges from light auburn to deep brown. The underbelly is lighter than the rest of the body, with a dark belly band across it. The cere (the soft skin at the base of the beak), the legs, and the feet are all yellow. The tail is uniformly red, and it is this trait that gives red-tailed hawks their name.
Immature red-tailed hawks look similar to adults. One difference is that immatures have yellowish-gray eyes that become dark brown as adults. (Preston and Beane, 1993)
Red-tailed hawks are native only to the Nearctic region. They are found throughout the United States and Canada, and into Mexico and Central America. Many birds are year round occupants although the birds of the far north migrate south during the fall to escape the harsh winter.
Red-tailed hawks live in a variety of habitats. In their habitat, they need open areas for hunting and several scattered perches. Some of the habitats that red-tailed hawks live in are scrub desert, grasslands, farm fields, pastures, parks, woodlands, and tropical rainforests. Red-tailed hawks prefer to build their nests at the edge of forests, in wooded fence rows, or in large trees surrounded by open areas. (Preston and Beane, 1993)
Red-tailed hawks usually begin breeding when they are three years old. They are monogamous, and mate with the same individual for many years. In fact, red-tailed hawks usually only change mates when their original mate dies. During courtship, the male and female soar together in circles for up to 10 minutes before mating. (Preston and Beane, 1993)
Red-tailed hawk nests are usually 28 to 38 inches wide. They are often used for several years in a row, and can be up to 3 feet tall. The male and female work together to build the nest in a tall tree, 4 to 21 meters above the ground. Where there are not trees to build nests in, red-tailed hawks build their nests on cliff ledges or on man-made structures such as buildings. The nests are made of twigs and lined with bark, pine needles, corn cobs, husks, stalks, aspen catkins and other soft plant materials. The hawks put fresh bark, twigs, and pine needles in the nest throughout the breeding season to keep it clean.
The female lays 1 to 5 eggs around the first week of April. The eggs are laid every other day and are incubated for 28 to 35 days. Both parents incubate the eggs. Males bring food to the female while she is on the nest. The newly-hatched chicks are helpless (altricial). During the nestling stage, the female broods the young, and the male provides most of the food to the female and the chicks. The female feeds the chicks by tearing the food into small pieces. The chicks begin to leave the nest after 42 to 46 days. They learn to fly and hunt, and leave the nest for good after 10 weeks or so. (Preston and Beane, 1993)
Both parents incubate the eggs. When the chicks are nestlings, the female broods them to protect them from predators and hot and cold temperatures. The male provides most of the food to the female and the chicks, and the female feeds the nestlings by tearing the food into small pieces. The chicks begin to leave the nest after 42 to 46 days. After they leave the nest, young red-tailed hawks usually stay close to their parents. They begin to fly about 3 weeks after they first begin to leave the nest, and begin to catch their own food 6 to 7 weeks after that. They become completely independent from their parents by about 10 weeks after fledging, at about 112 to 116 days old. (Preston and Beane, 1993)
Red-tailed hawks are relatively long-lived birds. While many of these birds die young (most live less than two years), those that survive the first few years can live for many years. The oldest known wild red-tailed hawk lived to at least 21.5 years old. In captivity, red-tailed hawks have lived for at least 29.5 years. (Preston and Beane, 1993)
Red-tailed hawks are active during the day (diurnal). Red-tailed hawk pairs remain together for years in the same territory. These birds are very territorial, and defend territories that range in size from about 1 to 4 square kilometers. The territory size depends on the amount of food, perches, and nest sites in the area. The female is usually the more aggressive partner around the nest itself, whereas the male more aggressively defends the territory boundaries. The birds will soar over their territory, mostly on clear days, looking for intruders. (Preston and Beane, 1993)
Home range sizes range from 1.3 to 5.2 square kilometers. The size of red-tailed hawk home ranges varies with the quality of habitat, the sex of the individual, and the season. (Preston and Beane, 1993)
Adult red-tailed hawks make a call that sounds like "kee-eeee-arrr." It is often described as sounding like a steam whistle. Young red-tailed hawks communicate with their parents by making soft, low "peep"-ing sounds.
Red-tailed hawks also communicate through body language. In an aggressive posture, the body and head of a red-tailed hawk are held upright, and its feathers are standing up. In submission, the hawk's head is lower to the ground and the feathers are smooth. Red-tailed hawks also display many aerial behaviors. In the talon-drop, during courtship, they swoop down trying to touch one another with their talons. Undulating-flight is an up and down movement that is mainly used in territorial display. In the dive-display, the bird performs a steep dive. This display signals that his territory is occupied.
Red-tailed hawks have excellent vision. This allows them to see prey movements very far away.
Red-tailed hawks feed on a wide variety of prey, using their powerful claws as weapons. Eighty to eighty-five percent of their diet consists of small rodents. Mammals as large as eastern cottontail rabbits may also taken. Reptiles and other birds make up the rest of the diet. Male red-winged blackbirds are common prey because they are so visible when guarding their nests. Red-tailed hawks do most of their hunting from a perch. They are not known to store food. (Preston and Beane, 1993)
Adult red-tailed hawks are large formidable birds, and have few predators. Most predation on this species occurs to eggs and nestlings. Great horned owls are known predators of red-tailed hawk nestlings. Corvids are known predators of eggs and nestlings. (Preston and Beane, 1993)
Red-tailed hawks play an important role in local ecosystems by helping to control the populations of small mammals, including rodents and rabbits. They also provide habitat for some small bird species, including house sparrows, that live in active red-tailed hawk nests.
There are no known negative effects of red-tailed hawks on humans.
Red-tailed hawks help farmers by eating mice, moles and other rodents that disturb their crops.
Red-tailed hawks have extended their geographic range over the last 100 years. This expansion is probably due to expansion of red-tailed hawk habitat. As this new habitat continues to change, red-tailed hawk populations may decrease.
The greatest threats to red-tailed hawk populations are shootings, collisions with automobiles, and human activities near nests. Lead poisoning from eating food items that contain lead shot also kills a number of red-tailed hawks each year.
Red-tailed hawks are protected under the U.S. Migratory Bird Act and CITES Appendix II. (Preston and Beane, 1993)
Albinism is relatively common in red-tailed hawks.
Red-tailed hawks are considered to be a sign of good luck in the Mescalero Apache tradition (Louie Chavez, personal communication).
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