Buteo lineatus

Geographic Range

Red-shouldered hawks are found in the Nearctic region. They breed throughout the eastern and northeast United States into southern Canada, and west of the Sierra Nevada in California. Populations of red-shouldered hawks in the eastern U.S. and California are resident. Populations that breed in the northeast U.S. and southern Canada migrate to northern Mexico for the winter.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Red-shouldered hawks usually inhabit mature deciduous or mixed deciduous-conifer forests and swamps. They build their nests 6 to 15 meters (20 to 60 feet) above the ground in the branches of deciduous trees in wet woodland areas. They prefer to have dead trees nearby, where they can perch and enjoy an unobstructed view of the forest floor.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

• Wetlands
• swamp swamp

Physical Description

Red-shouldered hawks are large, broad-winged hawks with a relatively long tails and heavy bodies. They show reverse sexual size dimorphism, meaning that females are larger than males. Female red-shouldered hawks average 700 g and 48 to 61 cm in length whereas males average 550 g and 43 to 58 cm in length. Adults have a wingspan of 92 to 107 cm (average 100 cm). Adult red-shouldered hawks have a brown head, a dark brown back and reddish underparts with dark brown streaks. Juveniles appear similar to adults, but have creamy underparts with dark brown spots and streaks. Both adults and juveniles have reddish lesser secondary upper wing coverts, which give the impression of red shoulders, giving this species its name. The tail of the both immature and mature red-shouldered hawks is dark brown with white bands.

Five subspecies of Buteo lineatus are recognized. These subspecies are separated based on geography and physical characteristics. The head and breast markings of the Florida subspecies, Buteo lineatus extimus and Buteo lineatus alleni , are slightly paler than other Red-shouldered hawks. The California subspecies, Buteo lineatus elegans , and the Texas subspecies, Buteo lineatus texanus , however, have vibrant, deep red markings on the lesser secondary upperwing coverts, underwing coverts and breast.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry
• polymorphic polymorphic

• Sexual Dimorphism
• female larger

Reproduction

Red-shouldered hawks are monogamous and territorial. Courtship displays occur on the breeding grounds, and involve soaring together in broad circles while calling, or soaring and diving toward one another. Males may also perform the "sky-dance" by soaring high in the air, and then making a series of steep dives, each followed by a wide spiral and rapid ascent. These courtship flights usually occur in late morning and early afternoon.

• Mating System
• monogamous monogamous

Red-shouldered hawks breed once per year between April and July, with peak activity occurring between early April and mid June. They often use the same nest from year to year, refurbishing it each spring. Both the male and female build or refurbish the nest, which is large and deep, constructed from sticks, twigs, shredded bark, leaves and green sprigs.

The female lays 3 to 4 white eggs with brown or lavender blotches over the course of 2 to 3 days. Incubation begins when the first or second egg is laid, and lasts for 33 days. Hatching is asynchronous, with up to 7 days between the first and last chick. The nestlings are altricial, and are brooded nearly constantly by the female for at least a week. The male brings food to the nest for the female and nestlings during the nestling stage, which lasts approximately 6 weeks. Chicks begin to leave the nest at 6 weeks, but are fed by the parents for another 8 to 10 weeks. Chicks become independent of the parents at 17 to 19 weeks old. After becoming independent, they may still roost in or near the nest at night. Red-shouldered hawks begin breeding when they are 1 year old or older.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Male and female red-shouldered hawks both protect the nest and incubate the eggs. The female broods the chicks during the nestling stage while the male does most of the hunting for the female and the chicks. Both parents feed the young during the nestling and fledgling stages.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
• post-independence association with parents

Lifespan/Longevity

Wild red-shouldered hawks live an average of 25.6 months. The oldest known red-shouldered hawk lived 19 years and 11 months.

Behavior

Red-shouldered hawks are solitary and territorial. They do not form flocks, even in the winter.

Most populations of red-shouldered hawks do not migrate. They stay in the same area year-round. Red-shouldered hawks that breed in the northern parts of their range (the northeast United States and southern Canada) migrate to northern Mexico for winter.

• Key Behaviors
• arboreal arboreal
• flies
• diurnal diurnal
• motile motile
• migratory migratory
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

Male red-shouldered hawks tend to have larger home ranges than females. The home range of both sexes is usually larger during the non-breeding season than during the breeding season. Home ranges typically range from 1.0 to 3.4 square kilometers.

Communication and Perception

Red-shouldered hawks use physical displays, such as courtship flights, and vocalizations to communicate. Biologists recognize seven different calls given by red-shouldered hawk adults. The most common call is "kee-aah". This call is used to announce that a territory is occupied, and when the birds are alarmed.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

The diet of red-shouldered hawks consists primarily of small mammals, the largest of these being rabbits and squirrels . Other food items include reptiles and amphibians, such as snakes , toads, frogs and lizards , small birds and large insects. Crayfish are important prey for red-shouldered hawks in some regions.

Red-shouldered hawks search for prey while perched on a treetop or soaring over woodlands. When they sight prey, they kill it by dropping directly onto it from the air. They may cache food near their nest for later consumption.

Red-shouldered hawks use sight and hearing to hunt successfully. They do not hunt by smell. Some key characteristics that make red-shouldered hawks especially well-adapted to hunting are sharp eyesight and broad wings. The shape and structure of red-shouldered hawks’ wings allow them to soar effortlessly for extended periods of time searching for prey. The hawks’ large eyes are situated to look forward. Although this means that the birds must turn their heads in order to keep prey in view, the orientation of their eyes affords them excellent depth perception. The high concentrations of light-sensitive cone cells in red-shouldered hawks’ eyes also provide good resolving power and very sharp vision.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• insects
• aquatic crustaceans

• Foraging Behavior
• stores or caches food stores or caches food

Predation

Incubating red-shouldered hawk adults, nestlings and eggs are vulnerable to predation by great-horned owls and raccoons . Non-incubating adults are not usually vulnerable to predation.

Ecosystem Roles

Red-shouldered hawks compete with other large birds, including golden eagles , prairie falcons , red-tailed hawks , barred owls and great-horned owls for territories. They provide food for their predators; primarily great horned owls and raccoons . They also host at least one blood parasite ( Leucocytozoa ) and several external parasites.

Economic Importance for Humans: Positive

Red-shouldered hawks prey on rodents that are agricultural pests.

• Positive Impacts
• controls pest population

Economic Importance for Humans: Negative

Though red-shouldered hawks primarily eat rodents and other small mammals, they occasionally attack poultry, making them a nuisance to farmers. Many of these hawks are killed annually by farmers for this reason. The nickname "hen hawk" for red-shouldered hawks comes from their tendency to take advantage of poultry farms.

• Negative Impacts
• crop pest

Conservation Status

Prior to 1900, this species was one of the most common hawks in eastern North America. Population densities declined substantially through most of the 20th century, probably due to hunting and destruction of wet hardwood forest habitat. Poisoning from insecticides and industrial pollutants and loss of habitat are major threats to this species. Disturbance of nesting pairs by human activity such as logging and climbing of nest trees also presents a serious threat to some populations.

This species is listed as threatened or endangered in several U.S. states, including Michigan. It is protected in the U.S. under the Migratory Bird Treaty Act. This species is also listed under CITES Appendix II, limiting international trade of individuals or body parts.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Kari Kirschbaum (author, editor), Animal Diversity Web.

Stephanie Miller (author), Cocoa Beach High School, Penny Mcdonald (editor), Cocoa Beach High School.

References

Callahan, P. 1974. The Magnificent Birds of Prey . New York: Holiday House.

Christopher, R. 1990. Book of North American Birds . Pleasantville: Reader's Digest.

Clark, W., B. Wheeler. 2001. A field guide to hawks of North America, 2nd Edition . New York: Houghton Miflin Company.

Crocoll, S. 1994. Red-shouldered hawk (Buteo lineatus). Pp. 1-20 in The Birds of North America , Vol. 107. Washington, DC: The American Ornithologist's Union.

Whetmore, A. 1965. Water, Prey, and Game Birds of North America . Chicago: National Geographic Society.

Woodward, C., A. Howell, N. Mayo. 1931. Florida Birds . Tampa: Florida Grower Press.