BIRDS
Status: Common, Native Summer Resident
 

FERRUGINOUS HAWK
(Buteo regalis)

Description

The ferruginous hawk is the largest of the North American buteos. Buteos are large hawks with stocky bodies, long, wide wings and long, broad tails. Typical adult ferruginous hawks are 22 to 27 inches in length (56-68.5 cm) with wingspans approaching 5 feet (150 cm). Sometimes called "big white bellies," these hawks are easier to identify in the field than many birds of prey. The hawk's back and the top surface of wings are brownish with rufous feather-edging. The head and face are chestnut-streaked with white, much paler than the back surface of the bird. The throat, breast, belly, tail and underwings are mostly white. A striking contrast is displayed in adult birds. The legs and flanks are chestnut-colored and form a dark "V" on the lower underbody, as displayed in flight. Often the white tail will show a pale, reddish, band near the tip. Although the light-colored form is most common, a dark phase occurs in 2 to 5 percent of the hawk's population. Dark phase hawks, although very uncommon, are a rich, dark brown over their entire body. The tail and flight feathers of the wings are the same as in light phase birds.
 

Distribution

The ferruginous hawk is a fairly common summer resident, particularly in the western half of South Dakota. East of the Missouri River, this species resides mostly in the northeast corner of the state. The hawk frequently winters in the state, especially during mild winters. Those birds within the population that do migrate, arrive in early April and tend to leave South Dakota by the end of September.

Natural History

Ferruginous hawks in South Dakota choose the open prairies and plains of the west and northeastern portions of the state. They prefer open, unwooded habitats. Ferruginous hawks, being very large birds, require a diet of large grassland mammals. In South Dakota they feed on jackrabbits, ground squirrels, prairie dogs, and pocket gophers. Hawks tend to concentrate their hunting in the early morning and late afternoon hours by pursuing prey in direct close to the ground chases. Research has estimated that the reduction in jackrabbit densities in the western states has had a direct negative effect on hawk populations and their breeding success.

Adults begin nest construction in April and continue through June in South Dakota. Nest sites may be in trees with commanding views, power-line structures, on the ground, on haystacks, or on cliffs. Nests are built from sticks and debris and occasionally old nests are used. These old nests grow larger every year, with the hawks adding more rubbish to the site, forming an immense platform. The hawks raise one brood per year, with three to four eggs. Unlike most buteos, these large hawks sometimes (during nesting season) hunt cooperatively for large prey.

Conservation Measures

The ferruginous hawk, like other large hawks, is still trying to recover from its staggeringly low population numbers of the 70's and 80's. In 1973, the hawk was placed in a "status undetermined" by the U.S. Fish & Wildlife Service. From 1971 to 1981, this species was on the Audubon Society's Blue List. This list provides early warning of those North American species undergoing population reductions. The bird was also listed as a species of "special concern" by the society from 1982 to 1986. In 1984 researchers estimated a North American population of ferruginous hawks of 3,000 to 4,000 breeding pairs, of which 500 to 1,000 were in Canada.

Recently, populations of these birds are increasing in North America. This trend is probably due to the nationwide ban of DDT and federal legislation prohibiting the shooting of all birds of prey. DDT is a persistent pesticide that threatens the existence of all birds of prey. Before its ban in 1972, DDT was used throughout the country for eliminating agricultural pests. The chemical accumulated in the body tissues of the larger predatory birds and drastically reduced their breeding success. This chemical buildup is referred to as biological magnification; the chemical is concentrated as it moves up the food chain.

We have learned from mistakes of the past. We now strive to correct the problem through ongoing legislation and habitat
modification. But the only true conservation measure is education. By teaching today's youth and others who share space with these magnificent birds, we can preserve the livelihood of all birds of prey. All living things are interconnected, and until we understand this idea, all life on earth is at risk.

References

Ehrlich, Paul R. et al. 1988. The Birders Handbook. New York: Simon & Schuester Inc.,
Field Guide to the Birds of North America, 2nd ed. 1987. Washington, D.C.: National Geographic Society,
Mansell, William. North American Birds of Prey. New York: William Morrow & Company, Inc., 1980.
Peterson, Roger T. A Field Guide to Western Birds, 2nd ed. 1961 Boston: Houghton Mifflin Company,
SDOU, The Birds of South Dakota, 2nd ed. , 1991. Aberdeen SD: NSU Press.
The Audubon Society Master Guide to Birding, 3 vol. 1983. New York: Alfred A. Knopf.
Welty, Joel C. The Life of Birds, 3rd ed. 1982. New York: Saunders College Publishing.

Selected Resources For Teachers

Birds of Prey Coloring Book, Dover Publications, 31 E. 2nd St., Mineola, NY 11501. 42 species illustrated.
Birds of Prey Poster , vol. I & II. Windsor/Nature Discovery, 1000 S. Bertlesen #14, Eugene OR. 97402. These are full color, high quality posters with original artwork of hawks.
Birds of Prey Poster and Mobile set, Education Services, Division of Wildlife, S.D. Department Game, Fish and Parks, 3305 West South Street, Rapid City, SD 57702. This set includes a full color poster with hawk and owl pictures, plus a mobile and fact sheets.
Birds of Prey Zoobook Series, Wildlife Education Ltd., 9820 Willow Creek Rd., Suite 300, San Diego, CA. 92131. ISBN:
0-937934-01-1.
Field Guide to the Birds of North America, 1987. The National Geographic Society, Easy to follow guide with great illustrations.
North American Birds of Prey, 1980, a book by William Mansell, with artwork by Gary Low. An informative text with beautiful paintings.

Written by:
Pat J. Buscher, Pierre, SD 57501. 1996.

Illustration by:
Frank Beebe, taken from The Complete Falconer with permission of Hancock House Publishers, 1431 Harrison Ave., Blaine, WA 98230.

Reviewed by:
Dr. Dan Tallman, Northern State University, Aberdeen, SD 57401.

Publication of the Ferruginous Hawk fact sheet was funded by the South Dakota Department of Game, Fish and Parks, Division of Wildlife, Pierre, SD.