Living Bird Magazine
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
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.