Soaring high over the grasslands and agricultural fields of western North America in summer, the Swainson’s hawk is a long-distance migrant that is considered uncommon at Malheur Refuge, typically encountered in spring and autumn at Malheur Refuge. 

Named after the English naturalist William Swainson (though he never saw one himself), Swainson’s hawks are medium-to-large raptors, roughly the size of a red-tailed hawk but slenderer overall, with long, pointed wings and a slim body. Their plumage varies, but most have a pale belly and dark bib across the chest, with brownish upperparts. In flight, the contrast between dark flight feathers and pale underwings is distinctive. 

These hawks breed across the interior West, from southern Canada through the Great Plains and into parts of California and the Southwest. They favor open landscapes such as grasslands, shrub-steppe, and farmlands, where they scan for prey from fence posts or on the wing. 

Swainson’s hawks undertake one of the longest-distance migrations of all North American raptors. After breeding, they fly up to 14,000 miles round-trip—in segments of up to 300 miles per day—to spend the winter in the vast pampas grasslands of Argentina. Along the way, they form large flocks, sometimes numbering in the thousands, making for a spectacular sight during spring and fall migrations. 

Unusually for a hawk, Swainson’s diet shifts dramatically with the seasons. During the breeding season, they hunt small mammals like voles and ground squirrels to feed their young. In their South American wintering grounds, they become primarily insectivorous, feasting on grasshoppers, crickets, and dragonflies. 

They are agile hunters, often gliding low over fields or hovering in place before pouncing on prey. They also exploit agricultural fields, which can be rich in both rodents and insects. 

Swainson’s hawks typically return to the same nesting territories each year. Nests are built in isolated trees, windbreaks, or even on utility poles, and both members of a pair share incubation and chick-rearing duties. They usually raise one brood per year, with two to four chicks. 

Once in decline due to habitat loss and pesticide exposure—particularly the use of toxic organophosphates in Argentina—the Swainson’s hawk population has rebounded thanks to conservation efforts and international cooperation throughout its extensive range. The species is currently listed as Least Concern by the IUCN, though localized threats remain, including continued agricultural intensification and habitat fragmentation.