Any of 42 species (family Vireonidae) of New World songbirds with a stout, slightly notched, hook-tipped bill that has fine bristles at the base.
Vireos are 4–7 in. (10–18 cm) long and are plain gray or greenish, with white or yellow touches. They glean insects from foliage in woodlands and thickets, repeating loud short phrases over and over. The nest is a cuplike structure suspended from a small fork in a branch. The red-eyed vireo ( Vireo olivaceus ), which breeds from southern Canada to Argentina, is 6 in. (15 cm) long and has a black-outlined, white eye stripe that contrasts with its gray crown.