The Cassin’s Vireo has a gray head and greenish upperparts, white spectacles, whitish underparts, and greenish wings with two wing bars.
FemaleThe sexes are similar.
Seasonal change in appearanceNone.
JuvenileJuveniles are similar to adults.
HabitatCassin’s Vireos inhabit coniferous and mixed forests.
DietCassin’s Vireos eat insects.
BehaviorCassin’s Vireos forage rather deliberately in trees.
Cassin’s Vireos breed across much of the far western U.S. and southwestern Canada. They winter in Mexico. The population appears to be increasing.
Bent Life History
Visit the Bent Life History for extensive additional information on the Cassin's Vireo.
The Cassin’s Vireo was formerly considered to be a subspecies of Solitary Vireo, a species since split into Plumbeous, Cassin’s, and Blue-headed Vireos.
Cassin’s Vireos actively defend their nests by scolding and even diving at intruders.
VocalizationsCalls include a series of "cheh" notes, while the song consists of a two-or-three syllable series of slurred notes.
The Cassin’s Vireo’s nest is a cup of leaves, weeds, bark fibers, and other plant materials, and is typically placed on a forked twig of a tree.
EggsNumber: Usually lay 4 eggs.
Color: White with darker markings.
Incubation and fledging:
The young hatch at about 13-14 days, and leave the nest in about another 13-14 days, though continuing to associate with the adults for some time.