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Status: Population size: 23,000 Photo by Cornell Laboratory of Ornithology.

Ferruginous Hawk
(Buteo regalis)

This species was on the 2002 WatchList, but is not on the 2007 WatchList. Please refer to http://web1.audubon.org/science/species/watchlist/techReport.php for information on the 2007 WatchList.

Named for its ferruginous (rust-colored) feathers, the Ferruginous Hawk is the largest North American member of the Buteo genus, which also includes the ubiquitous Red-tailed Hawk. Ferruginous Hawks are found in open arid regions of western North America where they feed primarily on small mammals especially ground squirrels, rabbits and prairie-dogs.

Identification
A large hawk that occurs in both light and dark morphs (plumage types). Light-morph birds are most common, and are distinguished by their light tail, and mostly pale undersides. In flight, the reddish feathers of the legs form a dark "V" against the white background of the belly and tail. When perched, the rufous feathers for which it is named are apparent on its back and wings. Dark-morph birds are dark brown, with varying amounts of rusty-red highlights on the back, wings and breast feathers. Light tail is conspicuous on otherwise dark bird. Sexes are similar in plumage.

Distribution and Population Trends
Found in the open plains, short-grass prairie and desert uplands that stretch from northern Mexico to southern Canada. Breeds from eastern Washington south to Arizona in the west and in the east from southern prairie sections of Alberta, Saskatchewan and Manitoba south to Texas. Audubon Important Bird Areas that support breeding Ferruginous Hawks include Colorado's Pawnee National Grasslands IBA and Washington's Fitzner-Eberhardt Arid Lands Ecology Reserve IBA. Important Bird Areas that have been identified as supporting the species in Canada include Saskatchewan's Maple Creek Grasslands IBA and Manitoba's Southwestern Manitoba Mixed-Grass Prairie IBA (http://www.ibacanada.com/main.htm).

Thought to be declining in parts of its range, but accurate numbers not available. Though it can still be found throughout most of its historical range, large portions of its preferred habitat have been converted for agriculture.

Ecology
These large raptors hunt for small mammals in open terrain. Ferruginous Hawks will often hunt from ground perches, and will pounce on prey as they move through the soil or when they surface from burrows. In winter small groups can often be found waiting in ambush near prairie-dog towns. Prairie-dogs, ground squirrels, rabbits and hares are its primary prey.

Breeds from April to August, though dates vary with location. Nesting sites can be found on cliffs, outcroppings or single trees, though in areas where such sites are not available this species may nest on the ground. Their nests are substantial structures, often over 1 m (more than 3ft) in height and diameter. Historical accounts speak of Ferruginous Hawk nests constructed with bison bones and lined with bison fur.

Threats
Primary threats are loss of habitat from agriculture and reduction in the number of available prey species due to habitat loss and deliberate eradication programs. For example, the Black-tailed Prairie-Dog, an important food source for Ferruginous Hawks, faced organized extermination campaigns by ranchers because they were perceived as competing for grass with cattle. The Black-tailed Prairie-Dog is now a candidate for protection under the Endangered Species Act (see: http://mountain-prairie.fws.gov/btprairiedog/).

Ferruginous Hawks were also hunted in the past, but this does not seem to be a threat at the moment. Small numbers are killed each year by collisions with power-lines and by automobiles while feeding on road-killed mammals.

Conservation
Conservation of grassland and shrub ecosystems in the western U.S. is a relatively recent concern and specific conservation efforts for this species are in early stages of implementation. Partners In Flight plans have been developed for a number of states and regions in which the species occurs and a recently organized Short-grass Prairie Bird Conservation Region initiative will include this species and its habitats as a major priority in the development of conservation projects. The Rocky Mountain Bird Observatory has a program called Prairie Partners that works with private landowners to manage their lands for the benefit of various prairie birds including Ferruginous Hawks.

A 1991 a petition to add the Ferruginous Hawk to the list of species protected under the Endangered Species Act was rejected by the U.S. Fish and Wildlife Service.

What Can You Do?
Audubon's Important Bird Area program is a vital tool for the conservation of Ferruginous Hawks as well as other species. To learn more about the Important Bird Areas programs in states where the species occurs and how you can help visit: http://www.audubon.org/bird/iba/.

Volunteers are crucial to the success of programs that monitor the status of populations of Ferruginous Hawks and other bird species. Audubon's Christmas Bird Count (CBC) is one of the longest-running citizen-science monitoring programs in the world and has helped to follow changes in the numbers and distribution of Ferruginous Hawks. To learn more about the CBC and how you can participate visit: http://www.audubon.org/bird/cbc.

U.S. National Wildlife Refuges provide essential habitat for the Ferruginous Hawk, and a great number of other species throughout the U.S. and its territories. Unfortunately, the refuge system is often under-funded during the U.S. government's budgeting process. To learn more about how you can help gain much needed funding for U.S. National Wildlife Refuges, visit: http://www.audubon.org/campaign/refuge_report/

References
Bechard, M. J. and Schmutz, J.A. 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, PA and The American Ornithologists' Union, Washington, D. C.

Ferguson-Lees, J. and Christie, D. A. 2001. Raptors of the World. Houghton Mifflin Company, New York.

Stattersfield, A.J., and D.R. Capper (Eds). 2000. Threatened Birds of the World. Lynx Editions and BirdLife International, Barcelona and Cambridge.