From Opus

Photo by Michael Woodruff
Spokane, Washington, May 2004

Vireo cassinii

[edit] Identification

11-14 cm

• Grey head, flanks, and whitish underparts
• Yellow flanks
• Olive green-grey back
• Bright green rump
• Brown black wings and tail
• Dull olive green side to chest
• Solid white eye spectacle
• 2 white wing bars
• Brown iris
• Black, grey based bill
• Grey blue legs
  

Sexes similar, female slightly duller

[edit] Similar Species

Blue-headed Vireo has brighter yellow flanks and more contrast between the head and back.

Plumbeous Vireo is duller with little contrast between the head and the back and lacks yellow on the flanks.

[edit] Distribution

Breeds from British Columbia and southwestern Alberta through central Idaho, across to coastal Washington and Oregon, south to southern California and in Baja California, Mexico. Recent results suggest that at least part of the US population after having bred in early parts of summer migrates to north-western Mexico where a second round of breeding takes place.

A small number overwinter in southeastern Arizona, while the winter range mostly involves Mexico but for some birds may extend south to Costa Rica.

[edit] Taxonomy

Formerly lumped along with the Blue-headed Vireo and Plumbeous Vireo into one species, the Solitary Vireo.

[edit] Subspecies^[1]

Two subspecies are recognized:

• V. c. cassinii:

• Southern British Columbia to northern Baja; winters to Guatemala

• V. c. lucasanas:

• Mountains of southern Baja California (Sierra de la Laguna)

[edit] Habitat

Open woodland.

[edit] Behaviour

[edit] Diet

The diet includes insects.

[edit] Breeding

The nest is a cup made from bark strips and down. The clutch consists of 2 to 5 white, brown spotted eggs.

[edit] References

1. Clements, JF. 2009. The Clements Checklist of Birds of the World. 6th ed., with updates to December 2009. Ithaca: Cornell Univ. Press. ISBN 978-0801445019.
2. Paper describing migration to second breeding area
3. Wikipedia
4. All About Birds

• List of references

[edit] External Links