Length 14 inches, extent of wings 36; bill along the ridge 11⁄12, along the edge 11⁄12; tarsus 1¾.
Adult Female. Plate CXVII. Fig. 2.
The female differs little from the male in colour, and is not much larger.
THE WARBLING FLYCATCHER OR VIREO.
Vireo gilvus, Bonap.
PLATE CXVIII. Male and Female.
While at the little village, now the city, of Camden, in New Jersey, where I had gone for the purpose of watching the passage of certain Warblers on their way north early in the month of May, I took lodgings in a street ornamented with a long avenue of tall Lombardy poplars, one of which almost touched my window. On it too I had the pleasure shortly afterwards of finding the nest of this interesting little bird. Never before had I seen it placed so low, and never before had I an opportunity of examining it, or of observing the particular habits of the species with so much advantage. The nest, although formed nearly in the same manner as several others, which I have since obtained by cutting them down with rifle balls, from the top twigs of the tall trees to which they were attached, instead of being fastened in the fork of a twig, was fixed to the body of the tree, and that of a branch coming off at a very acute angle. The birds were engaged in constructing it during eight days, working chiefly in the morning and evening. Previous to their selecting the spot, I frequently saw them examining the tree, warbling together as if congratulating each other on their good fortune in finding so snug a place. One morning I observed both of them at work; they had already attached some slender blades of grass to the knots on the branch and the bark of the trunk, and had given them a circular disposition. They continued working downwards and outwards, until the structure exhibited the form of their delicate tenement. Before the end of the second day, bits of hornets' nests and particles of corn-husks had been attached to it by pushing them between the rows of grass, and fixing them with silky substances. On the third day, the birds were absent, nor could I hear them anywhere in the neighbourhood, and thinking that a cat might have caught them from the edge of the roof, I despaired of seeing them again. On the fourth morning, however, their notes attracted my attention before I rose, and I had the pleasure of finding them at their labours. The materials which they now used consisted chiefly of extremely slender grasses, which the birds worked in a circular form within the frame which they had previously made. The little creatures were absent nearly an hour at a time, and returned together bringing the grass, which I concluded they found at a considerable distance. Going into the street to see in what direction they went, I watched them for some time, and followed them as they flew from tree to tree towards the river. There they stopped, and looked as if carefully watching me, on which I retired to a small distance, when they resumed their journey, and led me quite out of the village, to a large meadow, where stood an old hay stack. They alighted on it, and in a few minutes each had selected a blade of grass. Returning by the same route, they moved so slowly from one tree to another, that my patience was severely tried. Two other days were consumed in travelling for the same kind of grass. On the seventh I saw only the female at work, using wool and horse hair. The eighth was almost entirely spent by both in smoothing the inside. They would enter the nest, sit in it, turn round, and press the lining, I should suppose a hundred times or more in the course of an hour. The male had ceased to warble, and both birds exhibited great concern. They went off and returned so often that I actually became quite tired of this lesson in the art of nest-building, and perhaps I should not have looked at them more that day, had not the cat belonging to the house made her appearance just over my head, on the roof, within a few feet of the nest, and at times so very near the affrighted and innocent creatures, that my interest was at once renewed. I gave chase to grimalkin, and saved the Flycatchers at least for that season.
In the course of five days, an equal number of eggs was laid. They were small, of a rather narrow oval form, white, thinly spotted with reddish-black at the larger end. The birds sat alternately, though not with regularity as to time, and on the twelfth day of incubation the young came out. I observed that the male would bring insects to the female, and that after chopping and macerating them with her beak, she placed them in the mouth of her young with a care and delicacy which were not less curious than pleasing to me. Three or four days after, the male fed them also, and I thought that I saw them grow every time I turned from my drawing to peep at them.
On the fifteenth day, about eight in the morning, the little birds all stood on the border of the nest, and were fed as usual. They continued there the remainder of the day, and about sunset re-entered the nest. The old birds I had frequently observed roosted within about a foot above them. On the sixteenth day after their exclusion from the egg, they took to wing, and ascended the branches of the tree, with surprising ease and firmness. They were fed another day after, on the same tree, and roosted close together in a row on a small twig, the parents just above them. The next morning they flew across the street, and betook themselves to a fine peach-orchard several hundred yards from my lodging. Never had Huber watched the operations of his bees with more intentness than I had employed on this occasion, and I bade them adieu at last with great regret.
The principal food of this species consists of small black caterpillars, which that season infested all the poplars in the street. They searched for them in the manner of the Red-eyed Flycatcher and Blue-eyed Yellow Warbler, moving sidewise along the twigs, like the latter, now and then balancing themselves on the wing opposite their prey, and snapping it in the manner of the Muscicapa Ruticilla, sometimes alighting sidewise on the tree, seldom sallying forth in pursuit of insects more than a few yards, and always preferring to remain among the branches. I never saw either of the old birds disgorge pellets, as I have seen Pewees do.