copyright: Conan Guard
A large, narrow-winged buteo of the plains. Rufous above, whitish below, with a whitish or pale rufous tail and light patch on upper surface of primaries. Head often quite pale. Overhead, typical adults show a
dark V formed by the rufousthighs. Immatures lack this and also the rusty patches on the underwing. They show a white rump and a gray tail. Dark morphs (adults) overhead have dark wing linings, contrasting with white flight feathers and white tails.
Plains, prairies. Found at all seasons in very open and dry country. Inhabits dry grassland, sagebrush plains, saltbush and greasewood flats, rangeland, desert. In winter, also in agricultural country, including over plowed fields.
Mostly small to medium-sized mammals.
Feeds on most readily available small prey, such as young jackrabbits, ground squirrels, pocket gophers, kangaroo rats; also cottontails, mice, others. Also eats birds, snakes, large insects.
Behavior: Hunts by watching for prey while soaring high, flying low, or from a raised perch. Sometimes waits on ground near active burrow of pocket gopher, then catches the rodent as it surfaces.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern. [conservation status from birdlife.org]
Pairs may circle high above nesting territory, calling.
Nest: Site is usually in top of tree, 20-50 above ground, but can be as low as 6 (available trees may be very short). Sometimes nests on cliff or on ground. Nest is bulky structure of sticks and debris, lined with finer materials, including cow dung. Historically, some nests were built of bison bones and lined with bison dung. Nest may be reused and added to annually until it becomes huge.
Clutch size 2 -4, sometimes up to 6 or more. Pale bluish white fading to white, usually marked with brown. Incubation is by both sexes, but female does more, and male brings food to her. Incubation period 32-33 days.
Female remains with young at first; male brings food, female feeds it to young. After about 3 weeks, both parents hunt. Age of young at first flight about 40 -50 days.
Southwestern Canada, western United States. Winters southwestern United States, northern Mexico. Migration: Mostly a short-distance migrant; some southern breeders may be permanent residents. Very rarely strays east of normal range.
- spanwidth min.: 122 cm
- spanwidth max.: 142 cm
- size min.: 56 cm
- size max.: 69 cm
- incubation min.: 32 days
- incubation max.: 33 days
- fledging min.: 38 days
- fledging max.: 40 days
- broods 1
- eggs min.: 2
- eggs max.: 5
- Conservation Status