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red-shouldered hawk

Buteo lineatus

What do they look like?

Red-shouldered hawks are large, broad-winged hawks with a long tails and heavy bodies. Female red-shouldered hawks 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 look similar to adults, but have creamy underparts with dark brown spots and streaks. Both adults and juveniles have reddish upper wing coverts (feathers), which make them look like they have red shoulders. They also have dark brown tails with white bands.

There are five subspecies red-shouldered hawks (Buteo lineatus). (Christopher, 1990; Clark and Wheeler, 2001; Crocoll, 1994; Whetmore, 1965; Woodward, et al., 1931)

  • Sexual Dimorphism
  • female larger
  • Range mass
    550 to 700 g
    19.38 to 24.67 oz
  • Range length
    43 to 61 cm
    16.93 to 24.02 in
  • Range wingspan
    92 to 107 cm
    36.22 to 42.13 in
  • Average wingspan
    100 cm
    39.37 in
  • Average basal metabolic rate
    2.11 W
    AnAge

Where do they live?

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. (Christopher, 1990)

What kind of habitat do they need?

Red-shouldered hawks live in forests and swamps. They build their nests 6 to 15 meters (20 to 60 feet) above the ground in the branches of hardwood trees in wet woodland areas. They prefer to have dead trees nearby, where they can perch and see the forest floor. (Callahan, 1974; Crocoll, 1994; Woodward, et al., 1931)

How do they reproduce?

Red-shouldered hawks are monogamous and territorial. They perform courtship flights by soaring together in broad circles while calling, or soaring and diving toward one another. Males may also perform a "sky-dance" by soaring high in the air, and then making several steep dives. These courtship flights usually occur in late morning and early afternoon. (Crocoll, 1994)

Red-shouldered hawks breed once per year between April and July. They often use the same nest for several years, fixing it up each spring. The male and female both build the nest, which is large and deep and made from sticks, twigs, shredded bark, leaves and green sprigs.

The female lays 3 to 4 white eggs with brown or lavender blotches. This takes 2 to 3 days. The eggs are incubated for 33 days. The egg that was laid first hatches first. The nestlings are altricial, meaning that they are helpless and need to be cared for by the parents. The female broods the chicks for at least a week after they hatch. The male brings food to the nest for the female and nestlings during the nestling stage. Chicks begin to leave the nest at 6 weeks old, 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. (Callahan, 1974; Crocoll, 1994)

  • How often does reproduction occur?
    Red-shouldered hawks breed once yearly.
  • Breeding season
    Red-shouldered hawks breed between April and July, with peak activity occurring between early April and mid June.
  • Range eggs per season
    3 to 4
  • Average eggs per season
    3
    AnAge
  • Average time to hatching
    33 days
  • Average time to hatching
    33 days
    AnAge
  • Average fledging age
    6 weeks
  • Range time to independence
    17 to 19 weeks
  • Range age at sexual or reproductive maturity (female)
    1 (low) years
  • Range age at sexual or reproductive maturity (male)
    1 (low) years

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. (Crocoll, 1994)

  • Parental Investment
  • 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

How long do they live?

Wild red-shouldered hawks live an average of 25.6 months. The oldest known red-shouldered hawk lived 19 years and 11 months. (Crocoll, 1994)

  • Range lifespan
    Status: wild
    20 (high) years
  • Average lifespan
    Status: wild
    25.6 months
  • Average lifespan
    Status: wild
    239 months
    Bird Banding Laboratory

How do they behave?

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. (Callahan, 1974; Christopher, 1990; Crocoll, 1994; Woodward, et al., 1931)

  • Average territory size
    1.92 km^2

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. (Crocoll, 1994)

How do they communicate with each other?

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. (Crocoll, 1994)

What do they eat?

Red-shouldered hawks eat small mammals as big as rabbits and squirrels. They also eat reptiles, such as snakes and lizards, and amphibians, including toads and frogs. They also eat small birds and large insects. Crayfish are an important food for red-shouldered hawks in some regions.

Red-shouldered hawks search for prey by perching on top of a tall tree or soaring over woodlands. When they sight prey, they kill it by dropping down onto it from the air. They may store food near their nest to eat later. There is no information available about how red-shouldered hawks drink water.

Red-shouldered hawks use sight and hearing to hunt successfully. They do not hunt by smell. Red-shouldered hawks have very sharp eyesight and broad wings which allow them to be very successful hunters.

There is no information available about how red-shouldered hawks obtain water. (Callahan, 1974; Crocoll, 1994; Whetmore, 1965)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • insects
  • aquatic crustaceans

What eats them and how do they avoid being eaten?

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. (Crocoll, 1994)

What roles do they have in the ecosystem?

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. (Crocoll, 1994)

Do they cause problems?

Though red-shouldered hawks usually eat rodents and other small mammals, they occasionally eat poultry, making them a nuisance to farmers. Many of these hawks are killed annually by farmers for this reason. Red-shouldered hawks are sometimes called “hen hawk" because of this. (Callahan, 1974)

  • Ways that these animals might be a problem for humans
  • crop pest

How do they interact with us?

Red-shouldered hawks prey on rodents that are agricultural pests. (Callahan, 1974)

  • Ways that people benefit from these animals:
  • controls pest population

Are they endangered?

Before 1900, red-shouldered hawks were one of the most common hawk species in eastern North America. They have become less common because of hunting and destruction of their forest habitat. Red-shouldered hawks are also accidentally poisoned by insecticides. They often are not able to raise young when there is human disturbance, such as logging, near their nests.

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. (Crocoll, 1994)

Contributors

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

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

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that generate their own body heat through metabolic processes.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

visual

uses sight to communicate

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 A Poole, F Gill, eds. 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.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Miller, S. 2000. "Buteo lineatus" (On-line), Animal Diversity Web. Accessed April 21, 2014 at http://www.biokids.umich.edu/accounts/Buteo_lineatus/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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