Черноголовый виреон Vireo atricapilla

Small vireo with distinctive black head and bold white spectacles surrounding a red eye. Otherwise greenish above with white underparts, yellowish sides and two yellow wingbars. Females and immatures slightly duller than adult males. Found in shrubby habitats with oak and juniper, especially on hillsides. Migrates south to Mexico for the winter. Endangered; populations especially threatened by Brown-headed Cowbird nest parasitism.