Vireo cassinii
(Cassin's Vireo)

Order: Passeriformes
Order Description: Passerines
Family: Vireonidae
Family Description:Vireos

Physical Description:
5-6" (13-15 cm). Gray head with white spectacles and black eyes; olive-brown back, wings, and tail; wings have white and black barring; white below with yellow wash on flanksClick word for definition.

Similar Species- Gray and Hutton's vireos

Short, burry, whistled phrases

In Idaho, Cassin's Vireos nest to the north of the Snake River.
Breeds across portions of Canada, south to Baja California, central Honduras, western Texas, northern Minnesota, southern Ohio, southern Appalachians, and New Jersey. Winters from southern California, northern Mexico, and portions of southeastern U.S., south to Costa Rica and western Panama.

Found in mixed woodlands, humid montane forests, pine/oak, oak forests, and pinyon/juniper. During migrationClick word for definition and in winter, also found in variety of forests, woodlands, scrub, and thicket habitats, but prefers forest edges and semi-open situations.

Eats mostly insects, but will also eat some spiders and small fruits.

Builds cup-shaped nest in tree (usually coniferousClick word for definition). Forages among foliage and branches of trees and shrubs. Species is common host for Brown-headed Cowbird, especially near settled areas in western U.S.; cowbirds reduce vireo reproductive success.

Both sexes incubateClick word for definition 3- 5 eggs (usually 4), for probably 13-14 days.

Element Code: ABPBW01160(?)
Status: Protected nongame species
Global Rank: G5
State Rank: S5
National Rank: N5B,N5N

Species Update:
The Solitary Vireo species in Idaho has been recently reclassified into three new species: Cassin's, Plumbeous, and Blue-headed Vireos.

Important State References:
Hejl, S.J. and R.E. Woods. 1990. Bird assemblages in old-growth and rotation-aged Douglas-fir/Ponderosa pine stands in the northern Rocky Mountains: a preliminary assessment. Pp. 93-100 in D.M. Baumgartner and J.E. Lotan, eds., Proceedings of a Symposium on Interior Douglas-fir: the species and its management. Feb. 27, 1990, Spokane WA.

Information by C. Trost, 2000.
Original images provided by C. Trost,© 2000
Design by Ean Harker w/ Mike Legler©, 2000.