Swainson's Hawk

Swainson's Hawk

Details About The Swainson's Hawk

  • General Information

    Compared to other North American buteos, the Swainson’s Hawk appears slimmer, with thinner body and narrower wings. In flight, dark flight-feathers contrast with paler wing-linings; long wings tapered, pointed, and in perched birds reach or barely exceed tip of tail. Pale morph birds show dark breast-band or bib between lighter belly and chin. At all ages, most likely to be confused with Broad-winged Hawk.

    Latin Name: Buteo swainsoni
    Class: Aves
    Order: Accipitriformes
    Family: Accipitridae
    Length: 18-22 inches
    Weight: 1.5-3 pounds
    Wingspan: 47-54 inches
    Common Name: Black Hawk, Brown Hawk, Grasshopper Hawk, Locust Hawk
    Etymology: buteo (Latin) - "a kind of falcon or hawk" swainsoni - after William Swainson, English naturalist

  • Flight, Voice & Habitat

    The flight of the Swainson's Hawk is strong, buoyant, and graceful direct flapping flight with moderately deep wing-beats when not transporting prey. It will also exhibit soaring flight with wingtips elevated above its back in a shallow dihedral. This species will “kite” when foraging, especially in moderate to strong winds. Two adults in play, presumably a breeding pair, will repeatedly drop and catch a prey item in air.

    The alarm call of the Swainson's Hawk is given by both sexes either in flight or perched; described as a shrill, plaintive kreeeee.

    In their breeding range, the Swainson's Hawk forages in open stands of grass-dominated vegetation, sparse shrublands, and open woodlands. This species has adapted well to foraging in agricultural areas (wheat, alfalfa), but cannot forage in most crops that grow much higher than native grasses, making prey difficult to find. They are also attracted to flood irrigation, primarily in alfalfa fields, when prey takes refuge on field margins, and field burning, which forces prey to evacuate. Their wintering range is similar to breeding. At night, they perch in eucalyptus groves or windbreaks around farm sites.

  • Nesting

    The Swainson's Hawk typically nests in scattered trees in grassland, shrubland, or agricultural landscapes. Usually monogamous, both members of the pair build or refurbish nest. The male brings most nesting materials and does most construction. Nests are constructed of various freshly broken sticks, twigs, and debris; sometimes baling wire, rope, and pieces of farm equipment are incorporated into the nest. The lining consists of fresh leafy twigs from the nest tree, grass or hay, weed stalks and bark. This hawk typically lays 1 – 4 eggs (most commonly 2). The eggs hatch 34 – 35 days later. The female does nearly all of the incubation, and the male covers eggs only while female feeds away from nest for brief periods during the day. Male provides female with food. Nestlings fledge on average at 43 days of age.

  • Distribution

    Breeding range of the Swainson's Hawk is the western US and Canada as well as northern Mexico. The winter range is located on pampas of Argentina, also extending east into adjacent Uruguay. Nearly the entire population migrates annually between breeding areas in North America and wintering grounds in pampas of South America, a round-trip that can exceed 20,000 kilometers (12,500 miles). This species is threatened in some states because of habitat loss – farmland and grasslands being converted to suburbs – and because of pesticide use reducing their main prey species. Swainson's Hawks are not found in the Carolinas.

  • Food

    During breeding season, Swainson's Hawks eat mainly vertebrates, including mammals, birds, and reptiles. When not breeding, however, this hawk is atypical because it is almost exclusively insectivorous. On the wintering grounds, this species eats grasshoppers, butterflies and moths, and leaf beetles. During breeding season, they are a soaring, open-country hunter, often hunting from perches such as tree limbs, rocks, and elevated ground. Like other hawks, the Swainson's Hawk follows farm equipment ranging from horse-drawn implements to tractors and pesticide applicators to prey on rodents disturbed by these activities. They will catch flying insects in midair with their talons and eat them in flight. Generally an opportunistic predator, adults and fledglings are regularly observed on ground in pursuit of insects. On the ground, they run quickly and smoothly with head slightly lowered and often with wings slightly extended and raised.

  • Current Resident Birds

    Travis, a male Swainson's Hawk, moved to Carolina Raptor Center from the Great Basin Wildlife Rehabilitaiton Center in Baker, Nevada, in 2012. He was named by a donor for her brother. The name Travis means "traverser," or to pass along or move across. Swainson's Hawks are long distance migrants, traversing great distances, sometimes as far as Argentina during the winter months.

  • Fun Facts & Other Interesting Information

    Swainson's Hawks and Rough-legged Hawks are often confused. Birders have heated conversations around these two species during annual bird counts. No, I'm right. No, I'M right!

    No matter where this hawk travels, one thing is for sure. The Swainson’s Hawk is a friend to farmers throughout the Americas. These birds of prey are often seen in freshly mown fields, feasting on grasshoppers and other insects that can be detrimental to crops.