Vireo olivaceus
Order Passeriformes
Family Vireonidae
Adult. — Upper parts brownish, with a greenish tinge in strong light; crown gray, bordered on each side by a blackish line ; line over the eye white; dusky stripe through eye; under parts white, with no tinge of yellow.
Nest, a cup hung from a fork, from five to twenty-five feet up.
Eggs, white, spotted with brown, chiefly at the larger end.
The Red-eyed Vireo is a very common summer resident throughout New York and New England, arriving in May, and sometimes staying into October. It lives in deciduous trees, and may be found wherever they occur, the woods, orchards, plantations, village or city streets. It is a constant singer, so constant, in fact, that its song is very generally overlooked. It is only when one’s ears are opened that we realize how large a proportion of the daily chorus of bird-song is furnished by the Red-eye. The bird itself spends so much of his time among the leaves that unless one knows his song and follows it to its source one sees little of the singer. A male often sings for a long time on one twig, merely turning his head from side to side.
The song is made up of separate phrases of from two to four syllables, with either a rising or a falling inflection, as if the bird were carrying on a conversation. The phrases are separated by very short intervals, and vary greatly. Certain forms recur, but in no fixed order. Beginners have much difficulty in distinguishing the song of the Red-eyed from that of the Robin. This latter is a true song, an outburst of melody in which the same phrases are repeated in a definite sequence and after a certain interval. There is more power, too, in the voice. The Red-eyed’s phrases are each separated by a slight interval, so that it is impossible to say when the song is over; it goes on practically all day. The songs of the Yellow-throated and the Solitary Vireo [Blue-headed Vireo] resemble that of the Red-eyed in form, but each possesses more power, and the latter greater sweetness.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)