VIREOS, or GREENLET'S, a family (Vireonieis), of small fly-catching passerine birds, restricted to America, where they range from 'Patagonia to Canada. They have bills conical, much compressed, decurved at the end and notched, but scarcely toothed, with numer ous conspicuous rictal bristles; frontal feathers bristly and erect, or bent slightly fonvard; nostrils overhung by membrane; 10 primaries; tarsus usually longer than ntiddle toe and claw; lateral toes generally unequal. The vireos are all small, none of them exceeding about seven inches in length and their colors axe plain, generally more or less greenish above, with few conspicuous markings beyond wingubars and eye-stripes. The ins is frequently bright in color, red, yellow or pure white. The vireos are typically woodland birds, many of them preferring well-watered ravines, others swamps, while some inhabit open woods, parks or the trees of city streets. They are migratory and characteristically insectivorous and search for srnall caterpillars among the leaves or in cracks of the bark or capture insects on the wing, and they exhibit great activity in these pursuits. Some of the species also eat berries, particularly in the fall. Their nests are very characteristic, being deep cups composed of well-felted vege table fibres lined with fine grasses, often orna mented externally with bits of paper, lichens, etc., attached with spider's web and nearly al. ways pendent from the twigs of a horizontal fork in a low limb. The three or four eggs are pointed, of a crystalline whiteness and spotted with sharply defined reddish-brown markings. Generally the song is wealc, monot onous and repeated almost continuously, but some species are excellent songsters.
South and Central America is the headquar ters of this family of birds and there the great est number of generic types and the greatest variety in habits are exhibited, some of the species approaching the shrikes in structure and some exhibiting marked distinctions in the colors of the sexes. All of the 12 North American
species, some of which include several sub species, fall within the typical genus Vireo. While the differences in the colors, form of the often stout, shrike-lilce bill and proportions of the body are evident enough to the initiated, no group of birds is more confusing to the tyro in ornithology, and the reader is referred for descriptions of the species to some standard work on ornithology. The red-eyed vireo (V. olivaceaus) is generally the best known of the F.astern species. It is strictly a bird of the woods and is noted for its quarrelsomeness, activity and the energy and persistence with which it sings its simple lay continuously az it searches for insects throughout the hottest summer days. The warbling vireo ,(1/. gurus), of still wider range and locally almost as com mon, is a striking contrast to the last in that it forsakes the woods for the city parks and even the shade trees along much traveled streets and because of the surpassing sweetness of its song which, however, is so soft that it does not always reach the ear from the tree-tops where these birds dwell. A oath snore con spicuous songster, because of its greater power and marked- ventriloquistic ability, is the white eyed vireo (V. noveboracensis), a species which mit be sought in regions sparsely timbered or covered with a scrubby growth or in thickets bordering swamps. The blue-headed vireo (V. sciitorius) is recognitable as the largest and most stoutly built of North American species* the yellow-throated vireo (V. fictrifrotu), about equal in length but more slender the blue head, by its unusually bright colors, while the remaining species are chiefly restticted to the west and southvvest.