Vireo cassinii
adult
This species is very similar to both Blue-headed and Plumbeous vireos; its breeding range and habitat preferences help with separation. The sexes are broadly similar, although males are usually more brightly marked than females. All adults have a gray-green hood and a greenish-gray back. The underparts, including the throat, are mostly white with a dull yellow suffusion to the flanks. The white “spectacles” around the eyes are striking, and the dark wings have two pale (often subtly yellow) wingbars and pale margins to the inner flight feathers. The legs are blue-gray. Juveniles are similar to adults but overall duller.
Cassin’s Vireo is present as a breeding species in North America mainly from May to August, its range restricted to western mountain ranges. At other times of the year it is found mainly in Mexico, with a limited presence in southern Arizona. Migrant birds seen away from their breeding range can be hard to identify with certainty.
adult
FACT FILE
LENGTH 5 in (12.5 cm)
FOOD Insects and other invertebrates
HABITAT Open mountainside conifer forests
STATUS Common summer visitor
VOICE Song comprises a whistled tchee-oee followed by a churring tchewee. Call is a rasping tche
