22 1/2-25" (57-64 cm). Typical adults white below except for finely barred rufous legs, feathered to toes; upperparts reddish-brown with white patch at base of primaries (visible in flight); tail whitish or pale rufous, turning rusty toward tip; wing linings with some reddish mottling and dark wrist. Head often quite pale. Immatures have light thighs and lack rusty patches on wings; white rump and gray tail.
Similar Species- Red-tailed Hawk, Rough- legged Hawk, Swainson's Hawk
High pitched squeal, similar to, but shorter than the Red-tailed Hawk's.
Breeds from eastern Washington, southern Alberta, southern Saskatchewan, and southwestern Manitoba, south to eastern Oregon, Nevada, Arizona, New Mexico, north-central Texas, western Oklahoma, and western Kansas. Winters from southwestern and south-central U.S., south to Baja California and central mainland of Mexico.
Eats small mammals and reptiles (snakes and lizards), and occasionally eats birds (grouse, meadowlarks, etc.). Will also eat some insects. In Idaho, diet includes ground squirrels, rabbits, pocket gophers, kangaroo rats, mice, voles, lizards, and snakes.
Hunts from air or perch, most frequently near sunrise and sunset. Builds nest in tree or on cliff. Up to 8-10 nests per 100 km2 are possible if local conditions are favorable. Idaho study estimated average home range of males to be 7-8 km2; birds did not use habitats proportional to availability. In general, species is adversely affected by agricultural development. In Idaho, species is associated with nesting Swainson's Hawks, and commonly migrates south in fall, but resides in limited numbers in southern part of state. A 1985 southern Idaho survey located 72 occupied nests and revealed recent distribution is being maintained.
Female incubates 3-4 eggs for about 32-33 days; male provides food. Young fledge in 35-50 days (males before females), and depend on parents for several additional weeks (southern Idaho study reported average brood number of 3.2). clutch size, fledging rate, and/or breeding density tend to vary with prey availability (especially jackrabbits or ground squirrels). Female evidently does not often renest if clutch is lost. Individuals are easily disturbed by humans during early nesting season. There is no eveidence that yearlings breed.
|Status:||Protected nongame species|
Bechard, M.J., K.D. Hague-Bechard, and D.H. Porter. 1986. Historical and current distributions of Swainson's and Ferruginous Hawks in southern Idaho. Dept. Biol., Boise St. Univ., Boise. 58pp.