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Buteo regalisferruginous hawk

By Katherine Rogers

Geographic Range

The Ferruginous Hawk can be found in North America, as far north as Canada, south through western and central United States to northern Texas. It winters south to northern Mexico (del Hoyo, et. al. 1940).

Habitat

The Ferruginous Hawk is most often found in the interior in lowlands, plateaus, valleys, plains, rolling hills of grass land, agricultural land, ranches, and the edges of deserts (Clark 1987).

Physical Description

Ferruginous Hawks are usually between 50-66cm (20-26 in.) in length, have an average wingspan of 134-152cm (53-60 in.) and weigh 980-2030g (2.2-4.5 lb.). They are the largest hawks in North America, and are sexually dimorphic. The female hawk may be up to one-and-a half times larger than the male. "Ferruginous" is derived from the Latin Ferrugo, meaning, "rust", which is the predominant color of this hawk. Adults have a rusty color on their back and shoulders, which extends downward onto the legs. The under-part is a whitish color spotted with rufous. A view of the bird in flight will show that the leg feathers form a V shape against the belly of the hawk. When perched, the gray tips of the hawk's long and broad wings often reach the tip of their white, rust, and gray colored tail. Juvenile Ferruginous Hawks lack the rust colored legs and have less color on their backs (Malik 1987; Clark 1987).

  • Range mass
    980 to 2030 g
    34.54 to 71.54 oz

Reproduction

Ferruginous Hawks tend to breed in open territory, plains, prairies, and badlands. Nests are built on low cliffs, buttes, cut banks, shrubs, or trees, and occasionally on man-made structures or the ground. Sticks 2.5cm (1in.) in diameter, cow dung, bones, and grass are used in construction of nests. Ferruginous Hawks have a clutch of 2-6 eggs that are bluish white, marked with brown. The average size of the egg is 2.4" (61mm). The eggs are fertilized and laid in April, and incubate for approximately 28 days. Young fledge within 38-50 days. The parents share the responsibility of feeding the young until they become independent, usually after 30 to 60 days (Ehrich 1988; Clark 1987).

  • Average eggs per season
    3
    AnAge
  • Average time to hatching
    32 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    730 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    730 days
    AnAge

Lifespan/Longevity

Behavior

When courting, Ferruginous Hawks will soar with wings held arched above their backs. The male then darts at the female, their talons clasp and the pair display an aerial cartwheel. A pair of hawks mate for life (Clark 1987).

Communication and Perception

Food Habits

Ferruginous Hawks are carnivorous. They commonly hunt by flying low to the ground over open fields at high speeds, soaring high above, hovering, or swooping down from perches. Hawks use their excellent eyesight to spot their prey on the ground and then attack with talons. Ground squirrels, jackrabbits, and mice, as well as birds, reptiles, and amphibians are common prey for this hunter. Depending on the size of the prey, Ferruginous Hawks will swallow it whole, or tear off pieces of the animal with its beak. The portion of the food that can not be digested is then regurgitated into a food pellet (Zeiner 1990; Clark 1987).

Economic Importance for Humans: Positive

Ferruginous Hawks help to keep the rodent population in check.

Economic Importance for Humans: Negative

Ferruginous Hawks may be a problem for farmers, as they will occasionally prey upon chickens.

Conservation Status

Human agriculture and overgrazing have caused a great deal of disturbance in this hawk's nesting habitat. Many of these hawks have been shot while perched along roadsides. Federal law now protects all raptors, yet Ferruginous Hawks are still a species of special concern. In Washington Ferruginous Hawks are listed as Threatened (Leary 1998; Enrich 1988). They are also listed as near threatened by the IUCN.

Contributors

Katherine Rogers (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

acoustic

uses sound to communicate

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.

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

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

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.

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).

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.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

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

Clark, W. 1987. A Field Guide to Hawks North America. Boston, New York: Houghton Mifflin Company.

Ehrich, P., D. Dobkin, D. Wheye. 1988. The Birder's Handbook. New York, London, Toronto, Sydney, Tokyo, Singaporsingapor: Simon & Schuster inc..

Leary W. Alan, , Mazaika RoseMary, Bechard J. Marc. 1998. Factors Affecting the Size of Ferruginous Hawks. The Wilson Bulletin: 198-205.

Malick L. Donald, 1989. Field Guide to the Birds of North America. Washington, D.C.: National Geographic.

Zeiner C.Zeiner, , Laudenslayer, F. William, Mayer E Kenneth, White Marshall. November, 1990. California's Wildlife Volume 2 Birds. Sacramento, California: Department of Fish and Game.

del Hoyo, J., A. Elliott, J. Sargatal. 1994. Handbook of the Birds of the World V. 2 New World Vultures to Guineafowl. Barcelona: Lynx Edicions.

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