Ferruginous Hawk – State Wildlife Action Plan

Ferruginous Hawk

Photo Credit: U.S. Fish and Wildlife Service

The Ferruginous Hawk is the largest buteo in North America , with a wingspan of more than 140 cm. Adult males and females weigh on average 1,160 g and 1,700 g respectively. Both sexes are similar in appearance, but dimorphic in size with females being larger.
There are two color forms of Ferruginous Hawk, a light-morph and dark-morph, though the latter are rare in Oregon. Light-morph birds have stark white underparts, sometimes washed with rufous, with black, curved markings at the wrist. Their tarsi are rufous in color and fully feathered, and they have bare yellow feet. In flight they show white underparts including remiges and a long, broad rather pointed tail. Their back is rusty or rufous colored and the tops of the ends of the wings are darkish gray. Immatures are similar in appearance, but legs, flanks, and belly darkly spotted, lacking the rufous wash of adults.
Ferruginous Hawks are heavier chested than other buteos, which is particularly noticeable in flight. They perch in trees, on utility poles, buildings, fence posts, cliffs, or on the ground and often appear cumbersome when taking flight. In flight they soar with slightly uptilted wings. There are no subspecies recognized for the Ferruginous Hawk.

Overview

  • Species Common Name Ferruginous Hawk
  • Species Scientific Name Buteo regalis
  • Federal Listing Status Species of Concern
  • State Listing Status Sensitive

Ecoregions

Special needs

Ferruginous Hawks require open grassy areas and shrub-steppe habitats with scattered shrubs or trees for perching and nesting. Suitable nest sites include mature juniper or cottonwood trees near small streams, rocky outcrops with expansive views, rimrock formations, or undisturbed ground. The species has large area requirements and is particularly vulnerable to human presence and disturbance. In Oregon, key prey species include white-tailed jackrabbits, black-tailed jackrabbits, and ground squirrels. Changes in the distribution and abundance of these prey species can significantly affect the breeding success and population stability of Ferruginous Hawks.

Limiting factors

Populations of Ferruginous Hawks are limited by the availability of prey. Human disturbance during the nesting season can lead to nest abandonment or reduced breeding success. The species is also affected by the loss of mature juniper trees in otherwise suitable nesting areas. Land-use changes that alter the composition of native shrub-steppe habitats in eastern Oregon further reduce habitat suitability. In some areas, the conversion of juniper savannah to juniper woodland driven by fire suppression has negatively impacted nesting habitat suitability. Wind energy development poses both direct and indirect threats through habitat loss and fragmentation, behavioral disruption of adults near facilities, and mortality due to collisions. Energy infrastructure, including transmission lines and wind turbines, may also act as barriers to movement. Additional threats include illegal shooting and electrocution.

Conservation actions

• Provide diverse herbaceous and low shrub vegetation to support prey populations (e.g., jackrabbits and ground squirrels).
• Maintain known and potential nest site trees (e.g., mature juniper).
• Minimize human disturbance (including rodent control and chemical applications) within 0.6 miles of active nest sites from March 5 – June 15.
• Work cooperatively with agricultural landowners to maintain average field size of <40 acres and >25% of nesting areas in natural vegetation at priority sites.
• Continue to evaluate potential impacts from energy development near known habitats.

Key reference or plan

Rockwell, S.M., A.L. Holmes, B. Altman. 2022. Conservation Strategy for Landbirds in Sagebrush Steppe and Riparian Habitats of Eastern Oregon and Washington. Version 2.1. Read here

Washington State Recovery Plan for the Ferruginous Hawk. Read here