The flight of this Warbler is short, and exhibits undulating curves of great elegance. Its song is described as monotonous, consisting merely of continuous and tremulous sounds. Mr. Audubon found none beyond New Brunswick, and it has never been found in Nova Scotia so far as I am aware.
Both old and young birds remain in Massachusetts until late in October, and occasionally birds are seen as far to the north as Philadelphia in midwinter. At this season they abound in the pine forests of the Southern States, where they are at that time the most numerous of the Warblers, and where some are to be found throughout the year.
In the summer their food consists of the larvæ and eggs of certain kinds of insects. In the autumn they frequent the Southern gardens, feeding on the berries of the cornel, the box grape, and other small fruit. Mr. Nuttall states that their song is deficient both in compass and in variety, though not disagreeable. At times, he states, it approaches the simpler trills of the canary; but is usually a reverberating, gently rising or murmuring sound like er-r´-r´r´r´r´r´-ah, or in the springtime like twe twe-tw tw tw-tw tw, and sometimes like tsh-tsh-tsh-tw-tw-tw-tw, exhibiting a pleasing variety in its cadences. The note of the female is not unlike that of the Black and White Creeper.
On the 7th of June, Mr. Nuttall discovered a nest of this Warbler in a Virginia juniper-tree in Mount Auburn, some forty feet from the ground, and firmly fixed in the upright twigs of a close branch. It was a thin but very neat structure. Its principal material was the old and wiry stems of the Polygonum tenue, or knot-weed. These were circularly interlaced and inter-wound with rough linty fibres of asclepias and caterpillars’ webs. It was lined with a few bristles, slender root-fibres, a mat of the down of fern-stalks, and a few feathers. Mr. Nuttall saw several of these nests, all made in a similar manner. The eggs in the nest described were four, and far advanced towards hatching. They were white, with a slight tinge of green, and were freely sprinkled with small pale-brown spots, most numerous at the larger end, where they were aggregated on a more purplish ground. The female made some slight complaint, but immediately returned to the nest, though two of the eggs had been taken.
Mr. Nuttall kept a male of this species in confinement. It at once became very tame, fed gratefully from the hand, from the moment it was caught, on flies, small earthworms, and minced flesh, and would sit contentedly on any hand, walking directly into a dish of water offered for drink, without any precautions, or any signs of fear.
Mr. J. G. Shute found a nest of these Warblers in Woburn as early as May 8. It contained four eggs, the incubation of which had commenced. Three other nests were also found by him in the same locality, all of them
between the 8th and the 24th of May, and all built on branches of the red pine and near the top. Several nests of this Warbler, found in Lynn, Mass., by Mr. George O. Welch, are alike in their mode of construction, and differ in their materials from other accounts. They are all somewhat loosely put together, and are composed externally of fine strips of the bark of the red cedar, fine inner bark of several deciduous trees, dry stalks of plants, the exuviæ of insects, and fine dry grasses. The cavities of these nests, which are comparatively large and deep, were lined with the fur of the smaller mammals, the silky down of plants, and feathers. A few fine wiry roots were also intermingled. These nests are about two and a half inches in height and three in diameter.
The eggs of this Warbler are of a rounded oval shape, have an average length of .72 of an inch, and a breadth of .55. They resemble in size and appearance the eggs of the D. castanea, but the spots are more numerous, and the blotches larger and more generally distributed. The ground-color is a bluish-white. Scattered over this are subdued tintings of a fine delicate shade of purple, and upon this are distributed dots and blotches of a dark purplish-brown, mingled with a few lines almost black.
Dendroica montana, Baird.
BLUE MOUNTAIN WARBLER.