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Cassin's Vireo

ID Info
Cassin's Vireo by JMC Nature Photos
Vireos SilhouetteVireos
Cassin's VireoVireo cassinii
  • ORDER: Passeriformes
  • FAMILY: Vireonidae

Basic Description

A subtly handsome songbird with a bold white eyering, Cassin’s Vireo sings a loud, burry song while foraging slowly through the lower and middle parts of trees. It breeds in dry, open forests of far western North America. Outside the breeding season, this species often joins mixed-species flocks of woodland birds. Until 1997, Cassin’s Vireo was lumped with Blue-headed and Plumbeous Vireos into a single species called Solitary Vireo. Cassin’s is less colorful than Blue-headed but richer in olive tones than the mostly gray Plumbeous.

More ID Info
Range map for Cassin's Vireo
Year-roundBreedingMigrationNonbreeding
Range map provided by Birds of the World
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Find This Bird

Cassin’s Vireo nests in many open woodlands, from coastal forests to woodlands near treeline. Listen for its halting, rising-and-falling song, with its distinctly burry tone. The species also frequently makes a loud, fussing call, rendering it a fairly conspicuous bird within its habitat. Cassin’s Vireos forage at fairly low levels, on the outer parts of trees, so spotting one can be easy. This species is readily attracted to pishing sounds.

Other Names

  • Vireo de Cassin (Spanish)
  • Viréo de Cassin (French)
  • Cool Facts
    • The Cassin’s Vireo is named in honor of John Cassin, who was a nineteenth-century ornithologist with the Philadelphia Academy of Natural Sciences and published the first major book on the birds of the western United States. Other species named in his honor include Cassin’s Auklet, Cassin’s Kingbird, Cassin’s Sparrow, Cassin’s Finch, and the periodical 17-year cicada, Magicicada cassinii.
    • The loud, scolding call of the Cassin’s Vireo was memorably described by naturalist William Dawson in 1923 as a “rasping, nerve-grating war-cry.”
    • The Cassin's Vireo is the westernmost of the three species that were lumped together as the "Solitary Vireo" until 1997. In appearance it is intermediate between the brightly colored Blue-headed Vireo and the duller gray Plumbeous Vireo. Its song also is intermediate between the other two species: hoarser than the Blue-headed Vireo but slightly higher and with more clear phrases than the Plumbeous Vireo.