Vireo gilvus
Order Passeriformes
Family Vireonidae
Other names: Solitary Vireo
Adult.— Upper parts brownish-gray; under parts grayish-white, with a slight yellowish tinge on the belly; a whitish streak over eye, but no dark line through it.
Nest, a cup hung from a fork, from twenty to forty feet up.
Eggs, white, spotted with reddish-brown at the larger end.
The Warbling Vireo is a rather common summer resident of southern and central New England and of the lower Hudson Valley. In northern New York and New England it is confined to the neighborhood of villages in the valleys. In most of New England, in fact, it is a bird of the village street rather than of the woodland, though it is also found in tall trees along streams. It arrives a little earlier in May than the Red-eyed Vireo, and leaves in September.
The Warbling Vireo is less frequently seen than the Red-eyed, as it often stays for hours in tall shade-trees, but its song is uttered constantly, and affords an easy means of distinguishing it from its relative. It is a true warble, that is, a succession of smooth notes run into one another, and though repeated in the height of the breeding season more than four thousand times a day, never varies perceptibly. The song of the Red-eyed is made up of short phrases of almost endless variety. Beginners often have great difficulty in distinguishing the song of the Warbling Vireo from that of the Purple Finch. The song of the Finch is extremely rapid and energetic; the Vireo’s is deliberate and languid compared with the burst of melody that the Finch utters. The Warbling Vireo, after a period of silence in August, sings again in September, but only for a short time, early each morning. Both sexes have a querulous call-note, which suggests the mew of the Catbird.
If seen at close range, the Warbling Vireo may be distinguished from the Red-eyed by the different appearance of the side of the head; there is no dark streak through the eye, nor is the light line over the eye bordered above by a black line. From the following species it may be distinguished by the absence of a yellowish tinge on the throat and breast.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)