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Accipiter cooperiiCooper's hawk

By Tanya Dewey and Vladimir Perepelyuk

Geographic Range

Cooper's hawks are native to the Nearctic and Neotropical regions. They can be found throughout southern Canada and the United States. They winter as far north as the northern United States and southern Ontario, and as far south as Costa Rica. Cooper's hawks are year-round residents in most of the United States. (Tufts, 1986)

Habitat

Cooper's hawks are closely associated with deciduous and mixed forests and open woodland habitats such as woodlots, riparian woodlands, semiarid woodlands of the southwest, and other areas where the woodlands occur in patches. (Johnsgard, 1990)

Physical Description

Cooper's hawks are medium-sized birds with long, lean bodies. Individuals in the western part of the range tend to be smaller than those in the east. Male length ranges from 35 to 46 cm and length of female ranges from 42 to 50 cm. The average mass of males ranges from 280 g in western males to 349 g for eastern males. The average mass of females ranges from 439 g for western females to 566 g for eastern females. Cooper's hawks have a wingspan of 75 to 94 cm.

Adult Cooper's hawks have a dark blackish crown that is noticeably set off from a lighter nape. They have a blue-gray back and a tail that is crossed by several dark bands and has a distinct white band at its tip. In flight, Cooper's hawks exhibits a long barred tail and rather short, rounded wings.

The eyes of this hawk, like most predatory birds, face forward, giving it good depth perception for hunting and catching prey while flying at high speeds. The hooked bill is well adapted to tearing the flesh of prey. A swift flyer, Cooper's hawks have a rapid wingbeat and are able to negotiate heavily vegetated woodland habitats.

Cooper's hawks can be easily confused with sharp-shinned hawks, which are smaller (25 to 35 cm) and have a less distinct dark crown and a tail that is square at the tip, unlike the rounded tip of Cooper’s hawk’s tails. Cooper’s hawks also exhibit slower, stiffer wingbeats than sharp-shinned hawks. (Chipper Woods Bird Observatory, 1998; Johnsgard, 1990; Peterson and Peterson, 2002; Tufts, 1986)

  • Sexual Dimorphism
  • sexes alike
  • female larger
  • Range mass
    280 to 566 g
    9.87 to 19.95 oz
  • Range length
    35 to 50 cm
    13.78 to 19.69 in
  • Range wingspan
    75 to 94 cm
    29.53 to 37.01 in

Reproduction

Cooper’s hawks are monogamous, and many pairs mate for life. Pairs breed once per year and raise one brood per breeding season. The male chooses the nest site, but the female does the majority of the nest-building. Courtship activities include stylized flights with the wings held in a deep arc. Cooper’s hawks are territorial, and defend a territory around the nest.

Courtship activities include flight displays. For example, the male of a pair will fly around the female exposing his expanded under tail coverts to her. The male raises his wings high above the back and flies in a wide arc with slow, rhythmic flapping. Typically these display flights occur on bright, sunny days in mid-morning, and begin with both birds soaring high on thermals. The male and female may both participate in courtship flights. The male begins by diving toward the female, followed by a very slow-speed chase. Both birds move with a slow and exaggerated wingbeats alternated with glides in which the wings are held at a dihedral angle and the white under tail coverts are conspicuously spread. (Ehrlich, et al., 1988; Johnsgard, 1990; Peterson and Peterson, 2002; Whitfield, 1984)

Cooper's hawks begin breeding as early as March. Most individuals do not breed until they are at least two years old. Pairs build nests made of sticks and twigs and lined with bark, conifer needles and down. Males select most of the nest materials and do most of the nest building, although females contribute pieces of material occasionally. The female lays 3 to 6 (usually 4 to 5) bluish to greenish-white eggs that are usually spotted and soon become stained in the nest. The eggs hatch after 32 to 36 days, during which time they are incubated primarily by the female. During this time, the male provides most of the food for the female. After the eggs hatch, both parents tend the young who leave the nest after 27 to 34 days. Parents continue to provide food until the young become independent at about 8 weeks. (Chipper Woods Bird Observatory, 1998; Peterson and Peterson, 2002; Rosenfield and Bielefeldt, 1993; Stoper and Usinger, 1968)

  • Breeding interval
    Cooper's hawks breed once yearly.
  • Breeding season
    Cooper's hawks begin breeding as early as March.
  • Range eggs per season
    3 to 6
  • Average eggs per season
    4 to 5
  • Average eggs per season
    4
    AnAge
  • Range time to hatching
    32 to 36 days
  • Range fledging age
    27 to 34 days
  • Average time to independence
    2 months
  • Range age at sexual or reproductive maturity (female)
    1 (low) years
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Range age at sexual or reproductive maturity (male)
    2 (low) years
  • Average age at sexual or reproductive maturity (male)
    2 years

Both male and female Cooper’s hawks care for their chicks. During incubation, the female spends most of the time protecting the eggs and nest, and the male provides nearly all of her food. After hatching, the young are tended by both parents. The young are semialtricial at hatching, and thus require a significant parental investment to survive. The male continues to do most of the hunting during the hatchling stage. Both parents continue to provide food to the chicks until they become independent at about 8 weeks. (Ehrlich, et al., 1988)

  • Parental Investment
  • altricial
  • male parental care
  • female parental care
  • 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
    • protecting
      • male
      • female

Lifespan/Longevity

Cooper's hawks are known to live as long as 12 years in the wild. However, one study showed that the average age at death was as low as 16.3 months for wild Cooper's hawks. (Rosenfield and Bielefeldt, 1993)

  • Range lifespan
    Status: wild
    12 (high) years
  • Average lifespan
    Status: wild
    1.3 years
  • Average lifespan
    Status: wild
    244 months
    Bird Banding Laboratory

Behavior

Cooper's hawks are diurnal. They spend much of their time perched and waiting to ambush passing birds. Cooper's hawks migrate yearly between their summer breeding grounds and their southern winter range. They are mainly a solitary species that come together only to breed. (Rosenfield and Bielefeldt, 1993)

  • Range territory size
    0.7 to 1 km^2

Home Range

Little is known about the degree of territoriality among Cooper's hawks. However, they do appear to maintain a minimum distance between nests of 0.7 to 1.0 km. (Rosenfield and Bielefeldt, 1993)

Communication and Perception

Cooper's hawks communicate using vocalizations and displays. They probably use vocalizations more than visual displays, because their dense forested or woodland habitat prevents visual displays from being seen very far away. One study recorded 42 different calls made by females, 22 by males, and 14 by juveniles. Males have higher pitched voices than females.

Cooper's hawks rely heavily on eyesight to locate prey. Like all birds, Cooper's hawks perceive their environment through visual, auditory, tactile and chemical stimuli. (Rosenfield and Bielefeldt, 1993)

Food Habits

Cooper's hawks are predators primarily of birds and small mammals. They also occasionally feed upon reptiles and amphibians. When hunting, Cooper's hawks usually perch in a hidden location and watch for prey. They wait until their prey is unaware of their presence, then quickly swoop down and seize it. Bobwhites, starlings, red-winged blackbirds, eastern chipmunks, and squirrels are common prey for Cooper's hawks. Their short, rounded wings make them very maneuverable fliers in dense, forested habitats. These hawks also pursue prey on the ground by half running and half flying. The prey taken by an individual Cooper’s hawk is largely influenced by the size of the bird; larger hawks eat larger prey than smaller hawks. (Cybergeo, 1999; Ehrlich, et al., 1988; Rosenfield and Bielefeldt, 1993; Whitfield, 1984)

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

Predation

Adults, nestlings and eggs are vulnerable to predation by great horned owls, red-tailed hawks and northern goshawks. Eggs and nestlings are also vulnerable to predation by raccoons and American crows. (Rosenfield and Bielefeldt, 1993)

Ecosystem Roles

Cooper's hawks impact the populations of the animals they prey on. They are also hosts for several species of parasites, including larval dipterans, mallophagial lice, tapeworms and helminths. (Rosenfield and Bielefeldt, 1993)

Commensal/Parasitic Species
  • Internal parasites (Larval dipterans)
  • Mallophagial feather lice
  • Intestinal parasites (Tapeworms)
  • Internal parasites (Helminths)

Economic Importance for Humans: Positive

Cooper's hawks prey on small mammals that may be a pest to farmers or residential households. They also regulate populations of all their prey species, and thus contribute to healthy ecosystems. This species is occasionally used in falconry. (Rosenfield and Bielefeldt, 1993)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Cooper's hawks occasionally prey on domestic chickens in poultry farms. However, this occurs rather infrequently and is offset by Cooper's hawks consumption of pest species that can cause significant damage to farmers' crops. (Cybergeo, 1999)

Conservation Status

Cooper’s hawk populations declined as a result of the use of pesticides such as DDT, but have begun to recover since DDT was banned in 1972. One threat facing Cooper’s hawks today is degradation and loss of habitat. Management activities such as logging may make former habitat unsuitable for breeding.

Cooper's hawks are protected under the United States Migratory Bird Act and by CITES Appendix II which regulates the international trade of this species. They are listed under CITES Appendix III in Costa Rica. (Rosenfield and Bielefeldt, 1993)

Contributors

Tanya Dewey (author), University of Michigan-Ann Arbor, George Hammond (editor), Animal Diversity Web Staff, Rachelle Sterling (editor), Special Projects.

Kari Kirschbaum (editor), Animal Diversity Web Staff.

Vladimir Perepelyuk (author), Fresno City College, Carl Johansson (editor), Fresno City College.

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

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

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

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.

female parental care

parental care is carried out by females

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).

male parental care

parental care is carried out by males

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.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

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 savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

1996. Field guide to the birds of North America. Washington DC: National Geographic Society.

Chipper Woods Bird Observatory, 1998. "Cooper's Hawk" (On-line). Accessed July 10, 2000 at http://www.wbu.com./chipperwoods/photos/coophawk.htm.

Cybergeo, 1999. "Cooper's Hawk" (On-line). Accessed July 10, 2000 at http://www.cybergeo.com/birds/coopershawk.html.

Ehrlich, P., D. Dobkin, D. Wheye. 1988. The Birder's Handbook: A Field Guide to the Natural History of North American Birds. New York: Simon and Schuster.

Johnsgard, P. 1990. Hawks,Eagles, and Falcons of North America. Washington DC: Smithsonian Books.

Peterson, R., V. Peterson. 2002. A field guide to the birds of Eastern and Central North America, Fifth Edition. New York: Houghton Mifflin Company.

Robbins, C., B. Bruun, H. Zim. 2001. A guide to field identification: Birds of North America. New York: St. Martin's Press.

Rosenfield, R., J. Bielefeldt. 1993. Cooper's Hawk (Accipiter cooperii). A Poole, F Gill, eds. The Birds of North America, Vol. 75. Philadelphia, PA and Washington DC: The Academy of Natural Sciences and The American Ornithologist's Union.

Stoper, T., R. Usinger. 1968. Sierra Nevada Natural History. Los Angelos: University of California Press.

Tufts, R. 1986. "Birds of Nova Scotia -- Cooper's Hawk" (On-line). Accessed July 9, 2000 at http://museum.gov.ns.ca/mnh/nature/nsbirds/bns0089.htm.

Whitfield, P. 1984. Macmillan Illustrated Animal Encyclopedia. New York: Macmillan Publishing Co..

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