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Birds of North America, Vagrant Visitors, Introduced Birds and Possibilities

Cassin's Vireo

Viréo de Cassin

Vireo cassinii

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Species: The Cassin's Vireo (Vireo cassinii) came about after the Solitary Vireo was divided into three different vireo species, these being the Blue-Headed Vireo, Cassin's Vireo and Plumbeous Vireo. All three vireos are seen and recognized in different areas of North America. At different times of the year, migration periods and on winter grounds, these vireos may mix with one another. The Cassin's Vireo can be found in conifer and deciduous forests, parks and woodlands. It behaves in the same manner as the Blue-headed Vireo and can be observed moving deliberately through the branches, in search of insects.

Distinctions: The male and female are very similar looking in appearance. Has large bill with a visible hook at end of upper bill, same identifying features seen in other vireos. Dull gray crown, body and tail feathers, bold white lores and spectacles, two wing bars, green edges of tertials and primaries, greenish flanks and undertail, white throat and breast.

Voice: Nasal sounding, similar sounds to other vireo types, multiple call notes. Sings throughout the day even after breeding season.

Nesting: Three to five white eggs, speckled with brown or black spots. Suspended from a fork in branches of trees. The nest is composed of strips of wood bark, plant fibres and lined with fine grasses and spiderwebs.

Birds of North America
B L W W W Family Latin Name
5.5" 14cm 9.5" 24.1cm 0.6oz. 17g Vireonidae Vireo cassinii

  • Summer
  • Year Around
  • Winter

Distribution: Seen mostly long the western coast provinces and states, from northern British Columbia and Alberta to the tip of the California Baja, through the central states into Arizona and deep into Mexico.

References to Other Bird Sites:

Avibase - the world bird database

ABA - American Birding Association

AOS - The American Ornitholgy Society

ABC - American Bird Conservancy

eBird - TheCornellLab of Ornithology

NA - National Geographic

NAC - National Audubon Society

Classic Collection of North American Birds