The New International Encyclopædia/Vireo
VIR'EO (Lat. vireo, greenfinch, from virere, to be green, vigorous), or Greenlet. The common name of a family of about fifty insectivorous birds, having a plumage more or less tinted with green and olive. In the genus Vireo the bill is short, straight, notched, and hooked at the tip; wings long and pointed; toes of moderate length; tail moderate and even. There are about 30 species, a dozen of which occur in the United States, most of them migrating to and from South America and the West Indies. Many of these birds are singers, and the variety of song in the genus is great. All subsist exclusively upon insects, and are of immense service to the gardener and orchardist. All agree, also, in constructing a very artistic nest in the form of a cup of ribbon-like materials, such as grape-vine bark, ornamented with cobwebs, lichens, and the like; the typical form is shown on the Plate of Pensile Nests of Birds, under Nidification. The most familiar and widespread species in the United States is the red-eyed vireo (Vireo olivaceus), about six inches long; back and tail bright olive green, crown ashy, and a characteristic double line, dusky and white, over the eye, the iris of which is red. The white-eyed vireo (Vireo Noveboracensis) is very similar, but has a white iris. A more southerly species is Vireo barbatulus, called ‘Whip-Tom Kelley’ in Jamaica after its call-notes. Of the others, the most striking is the yellow-throated (Vireo flavifrons), which is bright olive green above, pure white beneath, and with the throat and breast bright yellow.