Hab. Eastern United States, north to Niagara Falls; Cuba (very rare); Guatemala; Veragua, Panama, and Bogota. Not recorded from Mexico (except Yucatan), or West Indies (except Cuba).
The autumnal adult plumage of both sexes is, in every respect, exactly like the spring dress. Young males in late summer are very similar to adult females, but are purer white below, and less uniform greenish-blue above, the dark stripes on sides of the crown and black centres to scapulars being quite conspicuous; the young female, at the same season, is similar in pattern to the adult, but is dull green above, without any tinge of blue, and light buffy-yellow below.
There is considerable variation in adult males, especially in the width of
the pectoral collar; one (No. 60,877, Mt. Carmel, Wabash Co., Ill., Aug. 9) has this entirely interrupted. In this individual there is no trace of a whitish supra-auricular streak; while others from the same locality, and obtained at the same date, have the band across the jugulum continuous, and a quite distinct white streak over the ear-coverts.
Habits. Of this somewhat rare Warbler very little is as yet well known. Its habits and distribution during the breeding-season need more light than we now possess to enable us to give its story with any degree of exactness. Its appearance in Pennsylvania, Ohio, Illinois, and Missouri early in May, when Warblers that go north to breed are on their way, at first suggested its belonging to that class. It is not known to proceed any farther north, except in accidental instances; though the writer has been assured, and has no reason to doubt the fact, that it abounds and breeds in the neighborhood of Niagara Falls. I can find no good evidence that it ever occurs in Massachusetts. Individuals have been obtained in northern South America, Panama, and Cuba. Dr. Woodhouse describes it as quite common in Texas and in the Indian Territory, where it breeds, as he obtained both the old and the young birds. It was also abundant among the timbered lands of the Arkansas and its tributaries. It was not obtained in any other of the government expeditions, nor was it found in Arizona by Dr. Coues. Mr. T. M. Trippe noticed a single individual near Orange, N. Y. Wilson supposed them to breed in Pennsylvania, though he was never able to find their nests. He usually met with these birds in marshes or on the borders of streams among the branches of poplars. Their habits were those of the Flycatchers. He saw none later than the 20th of August. Describing this species as the Blue-green Warbler, as met with by him on the banks of the Cumberland early in April, he mentions its gleaning for food among the upper branches of the tallest trees, rendering it difficult to be procured. Its resemblance, in habits, to Flycatchers, he again remarks. Its only note was a feeble cheep.
According to Audubon, this Warbler appears in Louisiana, where it also breeds early in spring, and leaves the first of October. Like all its family, it is quite lively, has a similar flight, moves sideways up and down the branches, and hangs from the ends of the twigs in its search for insects.
Mr. Audubon also states that the liveliness of the notes of this Warbler renders it conspicuous in the forests, the skirts of which it frequents. Its song, though neither loud nor of long continuance, he speaks of as extremely sweet and mellow. He found it as numerous in the State of Louisiana as any other Warbler, so that he could sometimes obtain five or six in a single walk.
The nest he describes as placed in the forks of a low tree or bush, partly pensile, projecting a little above the twigs to which it is attached, and extending below them nearly two inches. The outer part is composed of the fibres of vines and the stalks of herbaceous plants, with slender roots arranged in a circular manner. The nest is lined with fine dry fibres of the
Spanish moss. The eggs are five in number, of a pure white with a few reddish spots about the larger end. When disturbed during incubation, the female is said to trail along the branches with drooping wings and plaintive notes, in the manner of D. æstiva. After the young have left the nest, they move and hunt together, in company with their parents, evincing great activity in the pursuit of insects. They are also said to have a great partiality for trees the tops of which are thickly covered with grapevines, and to occasionally alight on tall weeds, feeding upon their seeds.
In his visit to Texas, Mr. Audubon met a large number of these birds apparently coming from Mexico. On one occasion he encountered a large flock on a small island.