Living Bird Magazine
Swainson's HawkButeo swainsoni
- ORDER: Accipitriformes
- FAMILY: Accipitridae
A classic species of the open country of the Great Plains and the West, Swainson’s Hawks soar on narrow wings or perch on fence posts and irrigation spouts. These elegant gray, white, and brown hawks hunt rodents in flight, wings held in a shallow V, or even run after insects on the ground. In fall, they take off for Argentine wintering grounds—one of the longest migrations of any American raptor—forming flocks of hundreds or thousands as they travel.More ID Info
Find This Bird
Your best bet for finding Swainson’s Hawks is during summer in open country west of the Mississippi River. They are perch conspicuously on utility poles, fence posts, and isolated trees in areas that otherwise lack such elevated perches. In perch-deprived areas, look for them standing on the ground in grassland or tilled agricultural fields. No other buteo species can be found in large numbers in such situations. During migration, they don’t move along ridgelines or lakeshores nearly as much as do other raptors. Instead, look for large flocks of soaring raptors over open country within their range, especially in April and September. If these are not Turkey Vultures, they are almost certainly Swainson's Hawks. At a few select migration spots including Hazel Bazemore Park (Corpus Christi, Texas) and a few sites in Middle America (Veracruz, Mexico; Kèköldie, Costa Rica; and Panama City, Panama) you can reliably see very large numbers of them passing south in fall. You can also see fairly large numbers in spring at the Santa Ana National Wildlife Refuge hawkwatch in south Texas.
- Aguililla de Swainson (Spanish)
- Buse de Swainson (French)
- Cool Facts
- The Swainson’s Hawk initially suffered from a case of mistaken identity, when a specimen collected in Canada in 1827 and illustrated by William Swainson was confused with the common buzzard (Buteo buteo) of Europe. A nephew of Emperor Napoleon eventually corrected the error: in 1832, while working in Philadelphia, French biologist Charles Lucien Bonaparte identified the hawk as a new species and named it after the original illustrator—although he based his own description on a drawing by John James Audubon.
- Swainson’s Hawk feed their chicks the usual “three r’s” of the North American buteo diet: rodents, rabbits, and reptiles. But when they’re not breeding, the adults switch to a diet made up almost exclusively of insects, especially grasshoppers and dragonflies.
- Groups of soaring or migrating hawks are called “kettles.” When it comes to forming kettles, Swainson’s Hawks are overachievers: they form flocks numbering in the tens of thousands, often mixing with Turkey Vultures, Broad-winged Hawks, and Mississippi Kites to create a virtual river of migrating birds. Their daytime migrations create a much-anticipated spectacle for birders who in fall and spring form their own flocks at well-known migratory points in the southern U.S., Mexico, and Central America to watch the birds stream by.
- The oldest known Swainson’s Hawk was at least 26 years, 1 month old. It was banded in 1986 in California, then recaptured and rereleased during banding operations, also in California, in 2012.