Photo: Glenn Bartley/Vireo

Priority Bird

Swainson's Hawk

Buteo swainsoni

This slim and graceful hawk is a common sight over grasslands of the Great Plains and the west, but only in summer: every autumn, most individuals migrate to southern South America. Although Swainson's Hawk is big enough to prey on rodents, snakes, and birds (and does so, while it is raising young), at most seasons it feeds heavily on large insects instead. Flocks are often seen sitting on the ground in fields where there are many grasshoppers or caterpillars.
Conservation status Has declined seriously in much of its nesting range, especially in California. Causes of decline not well understood.
Family Hawks and Eagles
Habitat Plains, dry grassland, farmland, ranch country. Breeds most commonly on northern Great Plains, in prairie regions with scattered groves of trees for nest sites. Less common in dry grassland farther west and in heavily farmed country. In migration, often pauses in fields where insect larvae may have been turned up by the plow.
This slim and graceful hawk is a common sight over grasslands of the Great Plains and the west, but only in summer: every autumn, most individuals migrate to southern South America. Although Swainson's Hawk is big enough to prey on rodents, snakes, and birds (and does so, while it is raising young), at most seasons it feeds heavily on large insects instead. Flocks are often seen sitting on the ground in fields where there are many grasshoppers or caterpillars.
Photo Gallery
  • adult, light morph
  • adult, intermediate morph
  • adult, dark morph
  • juvenile, dark morph
  • juvenile, intermediate morph
  • adult, light morph
  • juvenile, dark morph
  • adult, intermediate morph
  • adult, intermediate morph
  • juvenile, dark morph
  • adult, light morph
Feeding Behavior

May hunt by soaring over grassland, or by perching and scanning the ground. Skilled at catching flying insects in the air. When feeding on insects in fields, may catch them by running about on ground. May concentrate near grass fires, watching for prey driven into the open by the flames.


Eggs

2-3, sometimes 1 or 4. Pale bluish white fading to dull white, usually lightly spotted with brown. Incubation is almost all by the female, about 34-35 days. Male brings food to female during incubation period. Young: Both parents bring food for young, but at first female may remain with young much of time while male hunts. Young can fly about 42-44 days after hatching; may remain with parents until fall migration.


Young

Both parents bring food for young, but at first female may remain with young much of time while male hunts. Young can fly about 42-44 days after hatching; may remain with parents until fall migration.

Diet

Mostly small mammals and reptiles in early summer, large insects at other seasons. When feeding young, preys on ground squirrels, pocket gophers, mice, snakes, lizards, small birds; sometimes bats or carrion. At other seasons, diet shifts to mostly large insects. May feed heavily on grasshoppers and caterpillars in late summer. In winter in Argentina, follows and feeds on swarms of nomadic dragonflies.


Nesting

In courtship, members of pair engage in display flights, with circling and steep dives. On prairies with scattered groves of trees, may have conflicts with Great Horned Owl where both species attempt to nest in same grove. Nest site is usually in a tree or large shrub in open country, usually 15-30' above ground, but may be lower or higher; generally well hidden within foliage. May be built on top of old magpie nest. Sometimes nests on ledge of cliff or steep slope. Nest is a platform of sticks, lined with finer twigs, weeds. Often adds leafy green branches to nest.

Illustration © David Allen Sibley.
Learn more about these drawings.

Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Long-distance migrant, with most going to southern South America for winter. Often migrates in large flocks. May travel for several days without feeding. Mostly western, but every fall a handful of individuals show up on Atlantic Coast.

Download Our Bird Guide App

Migration

Long-distance migrant, with most going to southern South America for winter. Often migrates in large flocks. May travel for several days without feeding. Mostly western, but every fall a handful of individuals show up on Atlantic Coast.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon
Songs and Calls
Long, plaintive, whistled kreee.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
Learn more about this sound collection.

How climate change could affect this bird's range

In the broadest and most detailed study of its kind, Audubon scientists have used hundreds of thousands of citizen-science observations and sophisticated climate models to predict how birds in the U.S. and Canada will react to climate change.

Learn more

Read more: climate.audubon.org
Hawks and Eagles Hawk-like Birds

Swainson's Hawk

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season.

More on reading these maps.

Each map is a visual guide to where a particular bird species may find the climate conditions it needs to survive in the future. We call this the bird’s “climatic range.”

The colors indicate the season in which the bird may find suitable conditions— blue for winter, yellow for summer (breeding), and green for where they overlap (indicating their presence year-round).

The darker the shaded area, the more likely it is the bird species will find suitable climate conditions to survive there.

The outline of the approximate current range for each season remains fixed in each frame, allowing you to compare how the range will expand, contract, or shift in the future.

The first frame of the animation shows where the bird can find a suitable climate today (based on data from 2000). The next three frames predict where this bird’s suitable climate may shift in the future—one frame each for 2020, 2050, and 2080.

You can play or pause the animation with the orange button in the lower left, or select an individual frame to study by clicking on its year.

The darker the color, the more favorable the climate conditions are for survival. The outlined areas represent approximate current range for each season. More on reading these maps.
Winter
Summer

Winter Range
Summer Range
Both Seasons
Zoom InOut

Explore Similar Birds