VIREO

any of 42 species of New World birds constituting the family Vireonidae (order Passeriformes). This includes pepper-shrikes and shrike-vireosabout five tropical species sometimes separated as the families Cyclarhidae and Vireolaniidae, respectively. About 15 tropical forms are called greenletsformerly the usual name for all vireos. Vireos are the most primitive of the New World songbirds. The slightly notched and hook-tipped bill is stout but narrow, with fine bristles at the base. Vireos are 10 to 18 cm (4 to 7 inches) long and are plain gray or greenish in colour, with white or yellow touches (sexes alike). They occur in woodlands and thickets, where they glean insects from foliage, and repeat loud short phrases over and over. The vireo's nest is a cuplike structure suspended from a small fork of a branch, and the bird's eggs are white and sparsely speckled with reddish brown. The best-known and most widely distributed species of vireo is the red-eyed vireo (Vireo olivaceus), which breeds from southern Canada to Argentina. It is 15 cm (6 inches) long, with a black-outlined, white eye-stripe that contrasts with the bird's gray crown. Similar in general appearance is the white-eyed vireo (V. griseus).