THE VIREOS
The Vireos are a difficult group for the beginner. They are dull in color, they come at a time when other birds are abundant, and they do not, for the most part, have particularly noticeable songs. In identifying the Vireos it is well to remember that all of them move deliberately, turning the head from side to side pensively, and crawling about the branches in a very characteristic fashion. No Vireo has any white in the tail, as have many of the otherwise similarly colored warblers. Note that the first three species have no wing-bars; the other three have two wing-bars.
RED-EYED VIREO
Vireosylva olivacea (Linnæus)
Other Name.—Preacher Bird.
Description.—Size of English Sparrow. Adults: Top of head blue-gray; line above eye white, bordered above with a blackish line; line through eye blackish; rest of upperparts olive-green; underparts whitish, washed with olive-green and pale yellowish on sides; eyes reddish or red-brown. Young: Similar, but duller. Length: 6¼ inches.
Range in Pennsylvania.—Abundant migrant and summer resident from late April or early May to late September and October.
Nest.—A pensile cup made of vegetable fibers, cobwebs, and so forth, lined with grape-vine bark, placed on a branch of a low sapling, usually from 5 to 10 feet from the ground. Eggs: 3 or 4, white, with a few dark brown spots.
Warbling Vireo
Red-eyed Vireo
The oft-repeated song of this bird, which is delivered all during the warm hours of the summer days, has been responsible for the name “Preacher Bird.” This song, given while the bird searches for food among the leaves, is repeated at intervals of a few seconds, sometimes apparently for hours at a stretch. Look for the Red-eye in shady woodlands where there are deciduous trees. The harsh note of alarm is not unlike the well-known cry of the Catbird.
PHILADELPHIA VIREO
Vireosylva philadelphica Cassin
Description.—Like the Red-eyed Vireo, but smaller, with slightly shorter bill, greener upperparts, and rather decidedly yellower underparts.
Range in Pennsylvania.—A rather rare and little-known migrant in late April and early May and in September, found usually in alder thickets in the company of various species of the warbler family.
This species is not easy to identify in the field. Its song, which is like the Red-eye’s, but more rapidly delivered, may be heard in the spring; but in the fall, the chances are the bird will pass unnoticed since neither its song nor its color in any way attracts attention. All records are desirable.