Ferruginous Hawk (Buteo regalis)
Habitat
These buteos are restricted to natural grasslands and shrub-steppe habitat. They prefer undisturbed plains, high desert, sagebrush, or the edge of pinyon-juniper.
Physical Characteristics
These hawks are massive, long winged buteos that soar with wings held in a pronounced V-shape known as a dihedral. They have a large head with a wide yellow gape. There is a light and a dark morph, although dark birds make up a small proportion of the population. The light plumaged birds have a whitish head and breast and reddish-brown thighs. The upperparts are a mixture of blacks and browns with rufous highlights. The unbanded tail is mostly white with shades of gray. Legs are feathered to the toes. Dark birds vary, but are mostly dark with light-colored flight feathers. Sexes are similar with females being larger. Wingspan ranges from 48 to 60 inches (122-152 cm) and weights vary from 2.2 to 4.5 pounds (1-2.1 kg).
Life Span
A banded ferruginous hawk lived 20 years in the wild.
Diet
In the wild: Small and medium-sized mammals make up 80-90% of their prey. Black-tailed jackrabbits, ground squirrels and prairie dogs are some of the preferred items. Their wide gape makes them uniquely suited for swallowing larger mammals than other buteos. Some birds, reptiles and insects are also taken.
At the zoo:At the zoo: Rats, mice and quail
Reproduction
Ferruginous hawks appear to be monogamous and pair bonds may be long term. The pair may return to its territory year after year, and they usually have several alternate nest sites. Choice of nest site is limited in open country. Although adapted for ground nesting they seem to prefer elevated nest sites, when available. These sites include trees and shrubs, but cliffs, outcrops, utility structures and provided platforms are used. Unlike most large raptors, ferruginous hawks lay large clutches of two to six eggs. Incubation, mostly by the female, lasts for about a month.
Life Cycle
Females brood the young for the first three weeks while the male provides food for the family. Both sexes hunt after this. Young begin leaving the nest in 38 days. Fledglings can kill prey soon after leaving the nest, but tend to stay in the vicinity and remain dependent for several more weeks. Adults will often leave their nesting territory as soon as the young are catching prey. Mortality of juveniles is very high due to starvation, collisions with power lines and other factors.
Open Country Hunters
Long, broad, relatively pointed wings for a buteo allow ferruginous hawks to efficiently hunt their open habitats. They will often perch and wait for prey on a raised perch, or on the ground at a small mammal burrow. Their wing shape also allows them to hover, stationary in mid-air, searching the ground below for prey. They share habitat with other raptors including Swainson's and red-tailed hawks. They patrol their territories with high circling flights.
Location at the Zoo
A ferruginous hawk can be seen at the zoo's Raptor Center. Other birds of prey that can be viewed at the Raptor Center include the bald eagle, Harris's hawk, turkey vulture as well as spectacled and barred owls. The Raptor Center's Eagle Release Program has rehabilitated and released back into the wild more than 80 eagles. The zoo's Raptor Center assisted the Washington Department of Fish and Wildlife with a study to determine the winter range of the state's ferruginous hawks. Satellite radio transmitters were attached to birds from 1999 to 2002.
Conservation Connection
The ferruginous hawk's long-term survival is threatened by two main factors. They are dependent on natural grassland habitat, which is being converted to agricultural use across their range. Equally important, the rangeland mammals that they are specialized for preying upon are declining due to numerous human-induced causes.
These hawks were petitioned for listing under the federal Endangered Species Act in 1991, but were rejected. They are listed as threatened by several states, including Washington, and are listed as endangered by Oregon. Although mainly vulnerable due to habitat loss and degradation, shooting is still a factor, especially during winter. Ferruginous hawks' shy and retiring nature often mandates the use of fairly remote nest sites which are free of human disturbance. Protecting and enhancing nesting areas, large open areas and maintaining prey populations should help these birds survive. Artificial nest platforms have been used with some success. More research is necessary to determine factors during winter and migration that may influence long-term survival.
How You Can Help!
Efforts to save threatened and endangered raptors require cooperation and support at international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Recycle forest products. Eliminate or reduce pesticide use. Support breeding programs for endangered birds of prey at zoos and other animal care organizations. Let your elected representatives know your views about the conservation of migratory birds and their wild habitats.
Contact Woodland Park Zoo at webkeeper@zoo.org to find ways you can support conservation programs at the zoo. Discover more about raptors by contacting the Peregrine Fund at their Web site www.peregrinefund.org. Learn other ways you can help conserve wildlife and their habitats by visiting our How You Can Help page.
Sources and Suggested Reading
Bechard, M.J., and J.K. Schutz. 1995. Ferruginous Hawk (Buteo regalis). In The Birds of North America, No. 172 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and the American Ornithologists1 Union, Washington, DC. Weidensaul, Scott. 1996. Raptors: The Birds of Prey. Lyons and Burford, Publishers, New York, NY. 382 p.
Johnsgard, Paul A. 1990. Hawks, Eagles, & Falcons of North America. Smithsonian Institution, Washington, DC. 403 p.
Newton, Ian Dr. 1990. Birds of Prey, Facts On File, Inc., New York, NY. 240 p.
Weidensaul, Scott. 1996. Raptors: The Birds of Prey. Lyons & Burford, Publishers, New York, NY. 382 p.
For Kids!
Burnie, David. 1988. Bird (Eyewitness Books). Alfred A. Knopf, Inc., New York, NY. 64 p.
Zoobooks. 1986. Birds of Prey. Wildlife Education, Ltd., San Diego, CA. 16 p.