DENDROICA VIRENS VIRENS (Gmelin)
NORTHERN BLACK-THROATED GREEN WARBLER
Plates 36-38
HABITS
The northern black-throated green warbler I have always associated with the white pine woods, the delightful fragrance of fallen pine needles carpeting the forest floor, and the murmuring of the warm summer breeze. The song has been written as “trees, trees, murmuring trees,” appropriate words that seem to call vividly to mind the pretty little bird in its sylvan haunts and its delicious and soothing voice.
In southeastern Massachusetts, from late April until after midsummer one can seldom wander far in the thick groves of white pine (Pinus strobus), either in the open stands or in mixed woods where these pines predominate, without hearing the delightful drawling notes of this warbler, though the tiny singer in the tree-tops is not so easily seen. It is not, however, exclusively confined even in the breeding season to such woods, for sometimes we find it in open stands of pitch pines (Pinus rigida) or in old neglected pastures and hillsides where there is a scattered growth of red cedars (Juniperus virginiana).
Gerald Thayer wrote to Dr. Chapman (1907) that, in the Monadnock region of New Hampshire, the black-throated green warbler is “a very common or abundant summer bird through all the region, high and low; ranging from the pine woods of the lowest valleys to the half open copses of spruce and mountain ash along Monadnock’s rocky ridge—2,500 to 3,160 feet. * * * Though decidedly a forest Warbler, it favors second growth, and pasture-bordering copses, rather than the very heavy timber, and is particularly partial to dry white pine woods.”
Farther north, in the Canadian Zone, these warblers are at home in the forests of spruce and fir, but even here they seem to prefer pines, if they can find them, for Ora W. Knight (1908) says that in Maine “in the breeding season they resort to the pine woods by preference, and as a result are rather common in the pine barrens of the coastal plain. Inland the species is common, and while preferring the pines still, also occurs in rather open mixed woods where cedars, hemlocks and spruces predominate, and in northern Maine is found in spruce woods, seemingly because no other kinds are available.”
Farther west, in northern Michigan, this warbler breeds on the open jack pine plains and in mixed growths containing a fair percentage of other conifers. Frank A. Pitelka (1940b) writes: “During the breeding season the Black-throated Green Warbler is one of the more frequent Compsothlypids in the conifer regions of northern lower Michigan, though it is by no means to be included among the common birds. Locally it occurs in spruces of mature bog communities and in upland developmental forests of mixed pine and deciduous growth.”