Identification

Perching: Large hawk with white breast and white or dirty orange, unbanded tail. White feathers on chin and neck, long yellow beak (gape) extending back below eye, mottled rusty, white, and brown feathers on back.

Flying: White breast and white underwings in light morph bird. Almost all birds have white or dirty orange, unbanded tails. Upper wings show prominent white "windows" at base of primaries. Rusty leggings form a prominent "V" against whitish underparts of light morph adults in flight. Tends to fly in a straight line from perch to perch. Wings are long, broad, and pointed.

Nesting Habitat

Prairies and shrublands, eastern plains and northwestern plateaus. They build a stick nest in a tree, on a cliff face, or on the ground. In the Pawnee National Grassland, one nest was placed in a 30-foot high cottonwood near a paved highway, while another was located 4 feet off the ground on a small chalk cliff. They prey on rabbits and large rodents, including prairie dogs and ground squirrels.

Nesting Dates

Courtship: April to June

Incubation: mid-April to mid-July

Dependent nestlings: mid-May to late July

Incubation period is 30-34 days. Usually 2-4 young fledge 38-50 days after hatching.

Statewide Distribution and Population

Highest nesting densities occur on the southeastern and northeastern plains, with small numbers nesting from the Grand Valley northward to Wyoming. Only a few thousand pairs nest in the world, primarily on the high plains and in the Great Basin. Urban development and conversion of grassland to farmland threaten populations in many areas.

Federal and State Status

State special concern; Colorado State Wildlife Action Plan Tier 2 species.

Search and Nest Monitoring Protocol

Beginning in mid-April drive a set route, stopping every 500 m to scan all potential nest trees, cliffs, and ground sites (usually hilltops or rocky areas) with binoculars. Repeat every two weeks throughout the nesting season. Monitor active nests at two-week intervals from a fixed observation point located at least 800 m from the nest.

Recommended Nest Buffer Area

No foot traffic or recreational activity within 800 m of active nests or perches.

References

Bent, A. C. 1937. Life histories of North American birds of prey, part 1. U.S. National Museum Bulletin 167, Washington, D.C.

Houston, C. S., and M. J. Bechard. 1984. Decline of the Ferruginous Hawk in Saskatchewan. American Birds 38: 166-170.

Johnsgard, P. A. 1990. Hawks, eagles, and falcons of North America. Smithsonian Institution press, Washington, D.C.

Kingery, H. E., ed. 1998. Colorado breeding bird atlas. Colorado Bird Atlas Partnership, Denver.

Olendorff, R. R. 1972. The large birds of prey of the Pawnee National Grassland: nesting habits and productivity. USIBP Technical Report 151, Fort Collins.

Wickersham, L.E. 2016. The Second Colorado Breeding Bird Atlas. Colorado Bird Atlas Partnership, Denver.