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Overview
Swainson's hawk

Swainson's hawk

Wikipedia

Swainson's hawk is a large bird species in the Accipitriformes order. This species was named after William Swainson, a British naturalist. It is colloquially known as the grasshopper hawk or locust hawk, as it is very fond of Acrididae and will voraciously eat these insects whenever they are available.

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Distribution

Region

Western North America and South American Pampas

Typical Environment

Breeds in open country across the Great Plains, Great Basin, and western interior of North America, from southern Canada through the western United States into northern Mexico. Prefers prairies, shrubsteppe, and agricultural landscapes with scattered trees or shelterbelts for nesting. In the non-breeding season it concentrates in the Pampas, Chaco, and other open lowlands of Argentina, Paraguay, Uruguay, and adjacent Brazil. It favors broad, open habitats that allow soaring flight and ground foraging for insects.

Altitude Range

0–3000 m

Climate Zone

Temperate

Characteristics

Size43–56 cm
Wing Span117–137 cm
Male Weight0.8 kg
Female Weight1.1 kg
Life Expectancy16 years

Ease of Keeping

Beginner friendly: 1/5

Useful to know

Swainson's hawk undertakes one of the longest migrations of any North American raptor, traveling between western North America and the grasslands of South America. During migration it forms huge kettles of hundreds to thousands of birds soaring on thermals. Nicknamed the grasshopper or locust hawk, it switches heavily to large insects outside the breeding season. Populations rebounded after restrictions on harmful pesticides in parts of Argentina where they winter.

Gallery

Bird photo
Bird photo
Bird photo
in Ecuador

in Ecuador

Swainson's hawk migration route.30 birds were fitted with satellite tracking devices to produce this map. Incomplete: the birds also pass through Ecuador.

Swainson's hawk migration route.30 birds were fitted with satellite tracking devices to produce this map. Incomplete: the birds also pass through Ecuador.

Swainson's Hawk and prey, Weld County, Colorado

Swainson's Hawk and prey, Weld County, Colorado

A Swainson's hawk chick

A Swainson's hawk chick

Swainson's Hawk and nestlings, Weld County, Colorado

Swainson's Hawk and nestlings, Weld County, Colorado

Juvenile Swainson's hawk

Juvenile Swainson's hawk

Behaviour

Temperament

Territorial on breeding grounds but highly social in migration and on wintering grounds.

Flight Pattern

Soaring glider that rides thermals with minimal flapping; buoyant, long-winged flight.

Social Behavior

Typically nests as a monogamous pair, often reusing territories in trees, shelterbelts, or on utility structures near open foraging areas. Clutch size is usually 2–3 eggs; the female incubates more, while the male supplies prey. Outside the breeding season they gather in large flocks to roost and forage, especially where insect swarms are abundant.

Migratory Pattern

Seasonal migrant

Song Description

Calls are high, thin whistles and drawn-out keee notes typical of Buteo hawks. Vocal activity increases near the nest and during territorial displays, but they are generally quieter than some other raptors.

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