What do they look like?

Cooper's hawks are medium-sized birds with long, lean-bodies. Individuals in the western part of the range are usually smaller than those in the east. Male length ranges from 35 to 46 cm and length of females 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 and a lighter colored neck. The back is blue-gray and the tail is crossed by several dark bands and has a white band at the tip. The eyes of these hawks, like most predatory birds, face forward, giving them good depth perception for hunting and catching prey at high speeds. The hooked bill is important for tearing the flesh of their prey. In flight, Cooper's hawks display a long barred tail and rather short and rounded wings. Cooper's hawks beat their wings quickly and are able to fly very well through heavily wooded areas.

Cooper's hawks can sometimes be confused with sharp-shinned hawks, which are smaller (25 to 35 cm) and have a less distinct dark crown and a tail that is more square in shape.

Where in the world do they live?

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.

What kind of habitat do they need?

Cooper's Hawks live in deciduous and mixed forests. They also live in open woodland habitats such as woodlots, riparian woodlands, semi-arid woodlands of the southwest United States, and other areas where woodlands are found in patches.

How do they reproduce?

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 most of the nest-building. Courtship includes flight displays with wings held in a deep arc shape. 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 showing his under tail feathers to her. He raises his wings high above his back and flies in a wide arc with slow, rhythmic flapping. These display flights usually occur on bright, sunny days in midmorning, and begin with both birds soaring high on thermal currents. 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.

Cooper's hawks begin their breeding season early in the spring. As early as March, thy build nests made of sticks and twigs and lined with bark, conifer needles and down. 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. The female does most of the incubating, and the male provides food to her. After the eggs hatch, both parents care for the young, who leave the nest after 27 to 34 days. The parents continue to provide food to the chicks they become independent at about 8 weeks old. Most Cooper's hawks do not breed until they are at least two years old.

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, both parents tend the young. 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.

How long do they live?

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.

How do they behave?

Cooper's Hawks are diurnal. They spend much of their time sitting on a perch, waiting to ambush passing birds. Cooper's Hawks migrate yearly between their summer breeding grounds and their more southerly winter range.

We do not know much about how territorial Cooper's hawks are. However, they do build their nests at least 0.7 to 1.0 km away from their neighbors.

How do they communicate with each other?

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.

What do they eat?

Cooper's hawks eat mostly birds and small mammals. However, they also eat reptiles and amphibians when they are available. When hunting, Cooper's hawks usually perch in a hidden location and watch for prey. When they see prey, quickly swoop down and seize it. Bobwhites, starlings, blackbirds, chipmunks, and squirrels are common prey for Cooper's hawks. Their short, rounded wings make them very maneuverable flyers in dense, forested habitats. These hawks also chase prey on the ground, half running and half flying. The prey taken by an individual Cooper’s hawk depends on its size; larger hawks eat larger prey than smaller hawks.

How Cooper's hawks obtain water is not known.

What eats them and how do they avoid being eaten?

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.

What roles do they have in the ecosystem?

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.

Do they cause problems?

Cooper's hawks occasionally prey on domestic chickens in poultry farms.

How do they interact with us?

Cooper's Hawks prey on wild birds and rodents, which helps keep these populations in check.

Are they endangered?

Cooper’s hawk populations declined as birds were poisoned by pesticides such as DDT. Many of these chemicals have not been banned, and populations of Cooper's hawks are recovering. One threat facing Cooper’s hawks today is loss of habitat. Logging and other human activities may destroy Cooper's hawk habitat.

Cooper's hawks are protected under the U.S. Migratory Bird Act and CITES Appendix II. They are listed under CITES Appendix III in Costa Rica. In Michigan, they are listed as a species of special concern.

Contributors

Vladimir Perepelyuk (author), Fresno City College: October, 2000. Carl Johansson (editor), Fresno City College: October, 2000.

Kari Kirschbaum (editor), Animal Diversity Web Staff: October, 2004.

Tanya Dewey (author), Animal Diversity Web, University of Michigan Museum of Zoology.

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..