Buteo
regalis
(Ferruginous Hawk)
Physical
Description:
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
Song:
High pitched squeal, similar
to, but shorter than the Red-tailed Hawk's.
Distribution:
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.
Diet:
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.
Ecology:
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.
Reproduction:
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.
Conservation:
Element Code: | ABNKC19120 |
Status: | Protected nongame species |
Global Rank: | G4 |
State Rank: | S3,NTMB |
National Rank: | N4B,N4N |
Important
State References:
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.