Ferruginous Hawk (Buteo regalis)
Associated Species: Other species that may use habitat in a similar way and/or respond similarly
to threats, management, and conservation activities include Swainson's Hawk, American Kestrel,
Mourning Dove, Great Horned Owl, and Loggerhead Shrike.
Distribution: Ferruginous Hawks breed from eastern Washington east to southern
Saskatchewan, south to northern Texas, south and west through central New Mexico and central
Arizona, and as far west as southeastern Nevada. In Colorado, they are found primarily on the
eastern plains, in the grassland and lowland riparian habitat types. Small numbers of these hawks
nest in northwestern Colorado and the San Luis Valley.
Habitat Requirements: Ferruginous Hawks nest in isolated trees or small groves of trees, and
on other elevated sites such as rock outcrops, buttes, large shrubs, haystacks, and low cliffs.
Nests are situated adjacent to open areas such as grassland or shrubsteppe. These hawks are
closely associated with prairie dog colonies, especially in winter.
Ecology: In Colorado, nesting is initiated as early as mid March, and young fledge during late
June and July. Although they do breed in Colorado, Ferruginous Hawks are more common
during winter (November to March). Rabbits and hares are the most important prey items by
biomass, but prairie dogs and ground squirrels are the most important numerically.
Management Issues and Conservation Recommendations: Conversion of native grassland to
agricultural land has led to population declines. Management of grasslands for grazing is
considered compatible with healthy Ferruginous Hawk populations. Encourage public land
managers and private landowners to preserve native prairie.
Control of prey species (ground squirrels and prairie dogs) reduces Ferruginous Hawk
populations. Retain populations of the primary prey species at the highest levels compatible with
economic uses of the land.
Ferruginous Hawks are sensitive to disturbance at the nest; activities such as mineral extraction
near nests result in lower nest success or abandonment. Restrict activities within 0.8 km (0.5 mi)
of active nests.
Some birds are shot on the breeding and wintering grounds. Encourage strict enforcement of
extant game laws that protect this species.
Some nest trees are in shelterbelts or windbreaks or around abandoned homesteads; as those trees
are lost, suitable nest sites become scarcer. Preserve nest trees.
Status and Reasons for Concern: This species has a high conservation need locally and
throughout its range. The Ferruginous Hawk is a USFS Sensitive Species in Region 2, and a
CDOW Species of Special Concern. Within Physiographic Area 36, BBS data do not show a
statistically significant annual rate of change between 1966 and 1996 (P = 0.69; n = 25 routes).
Ferruginous Hawks were present on an average of 34.58% (SE = 3.53) of the BBS routes run in
Physiographic Area 36 in Colorado during 1988-1997, at an average abundance of 0.69 (SE =
0.09) individuals per route. The mean number of routes run each year was 29.2 (SE = 2.28).
This species is monitored by MCB with tracking transects.
Biological Objective: Maintain or increase the species' distribution and abundance, based upon
results from the BBS and MCB monitoring programs.
Selected References: Andrews and Righter 1992, Bechard and Schmutz 1995, Harmata 1981,