19-22" (48-56 cm). Dark brown above with reddish hood, white throat and body accentuated by a dark bib-like band across breast. Darker gray flight feathers highlight buffy wing linings. Indistinctly striped tail gray above often becoming white at the base, light below with dark border. They are frequently found in dark morphs, which don't have the white breast and belly. Also, th eleading edge of the wings in both morphs is usually white, in contrast to that of Red-tails.
Similar Species- Red-tailed, Rough-legged, and Ferruginous hawks
Shrill, monotone skreeeeee, also a shorter descending scream that trails off at the end.
Breeds in portions of Alaska and western Canada, east to Minnesota and Illinois, and south to southern California, parts of Mexico, Texas, and Missouri; eastern breeding limits are unstable, Winters from southwestern U.S. and southeastern Florida (irregularly), south to South America.
Vertebrates (mainly mammals such as young ground squirrels and pocket gophers) dominate diet during breeding season; invertebrates (especially crickets and grasshoppers) are common food at other times. Depending on availability, individuals also eat snakes, lizards, birds, amphibians, and some carrion. Concentrations of Swainson's Hawks foraging on grasshoppers have been documented in Idaho.
Hunts while soaring or from perch. Builds stick nest in tree, or occasionally on cliff. nesting density in suitable habitat varies from 0.1-1.6 nests/10 km2; nests average 1.4-2.4 km apart. May form pre- migratory aggregations in summer and migrate in immense flocks. Migrants may roost at night on ground in very large fields, and go without feeding during most of migration (with occasional feeding during initial and terminal stages). In Idaho, species is highly migratory (present between April and September and winters in Argentina). A 1985 survey in southern Idaho located 109 occupied nests and indicated that Swainson's Hawks were still a widespread common nester in state.
|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. Biology, Boise St. Univ., Boise. 58pp.