Setophaga virens
Order Passeriformes
Family Parulidae
♂ Adult male.— Back greenish in strong light; wing-bars broad, white; cheeks and forehead yellow; middle of throat, upper breast, and sides black; belly white, running up into the black area.
♀ Adult female.— The yellow cheeks duller, tinged with greenish; black throat almost obscured with gray; wing-bars white.
Immature.— Showing hardly any black on the throat.
Nest, from fifteen to fifty feet up in coniferous trees.
The Black-throated Green Warbler is a common summer resident of most of New York and New England; in northern New Jersey, the lower Hudson Valley, and south western Connecticut it occurs only as a migrant. It arrives late in April or early in May; northern individuals occur in September and early October in the mixed flocks of migrating warblers. It is the chief inhabitant of the white Green Warbler pines, where one hears continually its wheezy notes. It is also a common resident of the red cedar or savin groves of southern New England and of the spruces of northern New England and New York. In migration it is common in deciduous trees.
The song of this warbler has two forms, one quicker than the other; they may be written zee zee zu zi and zi zi zi zi zee’ zu zi. When a male is singing freely, he often keeps up a chipping note through the short intervals between the repetitions of his song.
The bird is seldom clearly seen, though its notes are so constant, but as it comes to the end of a twig, one gets from below a glimpse of the bright yellow cheeks, the black throat, and the entering angle of white between the black sides. The only other small bird with a black throat and yellow about the head is the Golden-winged Warbler. In this species the cheeks are clear black and white and only the top of the head is yellow; the black throat, too, covers only a small area, not extending down the sides, nor is the Golden-Winged Warbler found in pines. The songs of the two species and of the Black-throated Blue have something of the same quality of tone, but differ decidedly in form. The Black-throated Blue utters three notes, the last two drawled, and generally with a rising inflection. The song of the Golden-winged Warbler may be written zee zee-zee-zee, the first note long, the next three a bit lower and quicker.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)