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Accipiter striatussharp-shinned hawk

By Alaine Camfield

Geographic Range

Sharp-shinned hawks can be found throughout much of North America, including Mexico. In South America, they are found from Venezuela to northern Argentina. Most of the North American populations migrate to the southern parts of their range in winter. (Bildstein and Meyer, 2000; Sullivan, 1994)

Habitat

Sharp-shinned hawks are forest birds. They are found in pine, fir and aspen forests (among others). They can be found hunting in forest interior and edges from sea level to near alpine areas. Sharp-shinned hawks can also be found near rural, suburban and agricultural areas, where they often hunt at bird feeders. (Bildstein and Meyer, 2000; Campbell, et al., 1990; Snyder and Snyder, 1991; Sullivan, 1994)

Physical Description

Sharp-shinned hawks are the smallest accipiters (bird hawks) in North America. Males are 24 to 27 cm long and weigh 87 to 114 g. Females are larger, measuring 29 to 34 cm in length and weighing 150 to 218 g. Males have a wingspan of 53 to 56 cm and females 58 to 65 cm.

Sharp-shinned hawks have bluish-gray to slate colored upperparts, with darker coloration on the crown. Their underparts are white with brown bars and their short, rounded wings are dark above and light below. Females have fewer bars on the breast, and their upper parts are more brownish. Sharp-shinned hawks have a short, dark colored, hooked beak and yellow legs and feet. Their tail is square-tipped when not spread and has three to five dark stripes with a small white stripe on the tip. Molting does not change the adult’s appearance. Juveniles have more streaking and/or barring and paler coloration than adults. Sharp-shinned hawks look similar to Cooper’s hawks (Accipiter cooperii) but are smaller. (Bildstein and Meyer, 2000; Gough, et al., 1998; Snyder and Snyder, 1991; Wheeler and Clark, 1995)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • Range mass
    87 to 218 g
    3.07 to 7.68 oz
  • Range length
    24 to 34 cm
    9.45 to 13.39 in
  • Range wingspan
    53 to 65 cm
    20.87 to 25.59 in

Reproduction

Due to the secretive nature of sharp-shinned hawks, little is known about their mating behavior. They are known to have courtship flights and are presumed to be monogamous. (Bildstein and Meyer, 2000)

The breeding season of sharp-shinned hawks corresponds with the time of maximum prey availability; usually between late March and June. Sharp-shinned hawks begin building their nests soon after they arrive at the breeding ground. Nests are built in trees, usually below the canopy (2.4 to 19 m above ground). The nests are made of twigs and are often lined with bark chips. Both the male and female gather nesting material, but the female does most of the building. Nest sites are re-used from year to year and old nests are refurbished or new nests are built on top of old ones. The birds are territorial during the breeding season and defend their nest site against intruders.

Sharp-shinned hawks normally have only one brood per year and lay 4 to 5 eggs per clutch on average (range 3 to 8). Females usually lay eggs on alternate days. Eggs are white or bluish with dark spots, approximately 37 by 30 mm and weigh about 9 g (approximately 11 percent of the female’s body mass). Incubation lasts 21 to 35 days, and the eggs hatch within one to two days of each other. Females do most of the incubating, but males will bring food to females while they are on the nest. After hatching, the altricial chicks are brooded by the female for 16 to 23 days. The nestlings fledge after 21 to 32 days. Males usually fledge sooner than females. Young continue to receive parental care for about 3.5 weeks after fledging. Most sharp-shinned hawks begin to breed when they are two years old. (Bildstein and Meyer, 2000; Campbell, et al., 1990; Snyder and Snyder, 1991)

  • Breeding interval
    Sharp-shinned hawks usually have only one brood per year
  • Breeding season
    Late March to June
  • Range eggs per season
    3 to 8
  • Average eggs per season
    4.5
  • Average eggs per season
    4
    AnAge
  • Range time to hatching
    21 to 35 days
  • Range fledging age
    21 to 32 days
  • Average time to independence
    3.5 weeks
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    365 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    2 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    365 days
    AnAge

Female sharp-shinned hawks do most of the incubating, but males bring food to females while they are on the nest. After hatching, the altricial chicks are brooded by the female for 16 to 23 days. While the chicks are in the nest, the male brings food to the female who plucks it and feeds the chicks. Females also defend the nest against predators. The nestlings fledge after 21 to 32 days. Young continue to receive parental care for about 3.5 weeks after fledging. (Bildstein and Meyer, 2000; Campbell, et al., 1990; Snyder and Snyder, 1991)

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • male
      • female

Lifespan/Longevity

The longest recorded lifespan for a sharp-shinned hawk is 13 years. However, most do not live longer than 3 years. Causes of mortality include predators, hunting and collisions with cars and buildings. (Bildstein and Meyer, 2000; Sullivan, 1994)

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

Behavior

Sharp-shinned hawks are territorial during the breeding season. They deter intruders by calling, chasing and attacking. They are usually solitary, but can sometimes be found in small groups while migrating. Most North American populations are migratory; some fly distances of more than 1500 km. They leave their breeding grounds in August and return in March.

Sharp-shinned hawks show diurnal behavior patterns. Except while migrating, they usually fly below the canopy, using their tail to steer while in flight. (Bildstein and Meyer, 2000; Campbell, et al., 1990; Snyder and Snyder, 1991)

Home Range

Their home range is usually between 0.9 and 2.8 square km. (Bildstein and Meyer, 2000)

Communication and Perception

Sharp-shinned hawks are usually quite silent. They vocalize more frequently during the breeding season. Their alarm calls sound like “kek-kek-kek” or “kik-kik-kik.” Males make a “kip…kip” or “kew kew kew” call when approaching the nest, and females reply with a “keeeep.” Females and nestlings also make “eee” calls. (Bildstein and Meyer, 2000; Snyder and Snyder, 1991)

Food Habits

Small birds comprise ninety percent of a sharp-shinned hawk’s diet, which also includes small mammals and large insects. Sharp-shinned hawks mainly eat Passeriformes (perching birds), but also eat Falconiformes (diurnal birds of prey), Galliformes (chicken-like birds), Charadriiformes (shorebirds and relatives), Columbiformes (doves and pigeons), Apodiformes (swifts and hummingbirds) and Piciformes (woodpeckers and relatives). They often catch birds at feeders and take young birds from nests.

Sharp-shinned hawks are opportunistic hunters. They often hunt from a perch and dart out from hiding to catch prey. Their long, sharp talons help them to grab onto prey and their short bursts of high-speed flight help them to catch their prey. Sharp-shinned hawks pluck their prey before eating them. They get sufficient water from prey and do not need to drink. (Bildstein and Meyer, 2000; Sullivan, 1994)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • insects

Predation

Their secretive behavior and camouflaged nests help sharp-shinned hawks avoid predators. Known predators of sharp-shinned hawks include: bald eagles (Haliacetus leucocephalus), peregrine falcons (Falco peregrinus) and northern goshawks (Accipiter gentiles). (Bildstein and Meyer, 2000; Sullivan, 1994)

Ecosystem Roles

Sharp-shinned hawks are important members of their ecosystem. Because of their food habits they likely have a regulatory influence on local small bird populations. They are also an important food source for their predators.

Economic Importance for Humans: Positive

Sharp-shinned hawks may play a role in reducing pest species such as European starlings (Sturnus vulgaris) and house sparrows (Passer domesticus).

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Sharp-shinned hawks prey on songbirds, game birds and domestic fowl. (Sullivan, 1994)

Conservation Status

Sharp-shinned hawk populations experienced declines between the 1940’s and the 1970’s. The pesticide DDT caused eggshell thinning in many raptors and reduced the success of breeding pairs (eggs were often crushed underneath incubating parents). Conservation concerns today include declines in prey species, environmental contaminants and the fragmentation and reduction of contiguous forest habitat.

Sharp-shinned hawks are protected under the US Migratory Bird Treaty Act and are listed as Appendix II by CITES. (Bildstein and Meyer, 2000; Sullivan, 1994)

Other Comments

Geographic variation exists in the size and coloration of sharp-shinned hawks. There are ten recognized subspecies of Accipiter striatus. Accipiter striatus velox is the most common subspecies in North America.

Sharp-shinned hawks are closely related to Eurasian sparrowhawks (Accipiter nisus) and rufous-breasted sparrowhawks (Accipiter rufiuentris). (Bildstein and Meyer, 2000; Sullivan, 1994)

Contributors

Alaine Camfield (author), Animal Diversity Web.

Kari Kirschbaum (editor), Animal Diversity Web.

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

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

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. Synapomorphy of the Bilateria.

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 use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

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.

seasonal breeding

breeding is confined to a particular season

sexual

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

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

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

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

Bildstein, K., K. Meyer. 2000. Sharp-shinned hawk (Accipiter striatus). A Poole, F Gill, eds. In The Birds of North America, No. 482. Philadelphia, PA: The Birds of North America, Inc.

Campbell, R., N. Dawe, I. McTaggart-Cowan, J. Cooper, G. Kaiser, M. McNall. 1990. The Birds of British Columbia, Volume II: Non-passerines, Diurnal Birds of Prey through Woodpeckers. Victoria: The Royal British Columbia Museum.

Gough, G., J. Sauer, M. Iliff. 1998. "Sharp-shinned hawk (Accipiter striatus)" (On-line). Patuxent Bird Identification Infocenter. Accessed February 25, 2004 at http://www.mbr-pwrc.usgs.gov/id/framlst/i3320id.html.

Snyder, N., H. Snyder. 1991. Birds of Prey: Natural History and Conservation of North American Raptors. Stillwater, MN: Voyageur Press.

Sullivan, J. 1994. "Accipiter striatus" (On-line). Fire Effects Information System. Accessed February 25, 2004 at http://www.fs.fed.us/database/feis/wildlife/bird/acst/.

Wheeler, B., W. Clark. 1995. A Photographic Guide to North American Raptors. London: Academic Press.

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