Guide to North American Birds
Conservation status Great variation in annual numbers makes it difficult to monitor overall population. Apparently still widespread and common.
Family New World Sparrows
Habitat Desert grassland, brushy fields. Breeds in a variety of situations having good ground cover of grass and low shrubs; ranges from open grassland with only scattered shrubs to brushy areas with grassy understory. In migration and winter, also found in pure grassland, brushy areas, deserts.
In dry grassland country of the Southwest in summer, this plain brown sparrow is often seen flying up from a bush top and then fluttering down in a 'skylarking' display, giving a song of sweet trills and notes. Cassin's Sparrows are sometimes very common, but they are irregular, big numbers often appearing in an area after good rains have turned the prairies green. With their nomadic tendencies, they sometimes turn up far outside their normal range, with scattered records from coast to coast.

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Feeding Behavior

Forages mostly or entirely on the ground, hopping about in relatively open areas, taking items from the ground or from plant stems.


Eggs

3-5, usually 4. White, unmarked. Details of incubation are not well known. Young: Both parents feed the nestlings. Age at which young leave the nest is not well known.


Young

Both parents feed the nestlings. Age at which young leave the nest is not well known.

Diet

Mainly insects and seeds. Summer diet is partly to mostly insects, especially grasshoppers, caterpillars, moths, and beetles, also many others. Young are fed almost entirely on insects. Also eats seeds, especially in fall and winter, mainly those of weeds and grasses.


Nesting

Somewhat irregular in its nesting, especially in western and northern parts of range; may appear in numbers and breed only in years with good rainfall. Male advertises territory with flight song display, flying up to about 20' and then gliding and fluttering down, while singing. In courtship, male may chase female, or may display with wings and tail partly spread and fluttering. Nest site is usually on the ground, well hidden among weeds or at the base of a bush. Sometimes up to a foot above ground in a low shrub. Nest is an open cup made of dry grass, weed stems, bark, plant fibers, lined with fine grass.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

In many areas, seasonal occurrence is very irregular; may be present in large numbers one summer, absent the next. Winter numbers in Southwest are also quite variable. Strays sometimes wander far, having reached eastern Canada.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon

See a fully interactive migration map for this species on the Bird Migration Explorer.

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Songs and Calls

4 loud, melodious, clear whistles, uttered from the tops of tall grass stalks and also in flight. Second note is prolonged and quavering; third note is lowest.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How Climate Change Will Reshape the Range of the Cassin's Sparrow

Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.

Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.

Climate Threats Near You
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Climate threats facing the Cassin's Sparrow

Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.