Life Histories of North American Wood Warblers, Part One and Part Two. Arthur Cleveland Bent
the stump,” he says, “is filled with old leaves, and the nest proper is made chiefly of strips of bark with grass and fiber.” Guy H. Briggs (1900) reports a nest “in a decayed hemlock stump, fifteen inches from the ground.” In such cases, of course, while the nest is well above the ground level, it rests on a firm foundation.
Audubon (1841) says: “In Louisiana, its nest is usually placed in some small hole in a tree,” but he quotes a letter to him from Dr. T. M. Brewer on the subject, thus: “This bird, which you speak of as breeding in the hollows of trees, with us always builds its nest on the ground. I say always, because I never knew it to lay anywhere else. I have by me a nest brought to me by Mr. Appleton from Batternits, New York, which was found in the drain of the house in which he resided.”
Minot (1877) speaks of two nests found near Boston, Mass., well above the ground. He says: “The first was in a pine grove, in the cavity of a tree rent by lightning, and about five feet from the ground, and the other on the top of a low birch stump, which stood in a grove of white oaks.”
Gordon Boit Wellman (1905) states: “Toward the last of the incubation time one of the birds was constantly on the nest. I found the male sitting usually at about dusk, but I think the female sat on the eggs over night.”
Eggs.—[Author’s Note: The black-and-white warbler usually lays 4 or 5 eggs to a set, normally 5, seldom fewer or more. These are ovate to short ovate and slightly glossy. The ground color is white or creamy white. Some are finely sprinkled over the entire surface with “cinnamon-brown,” “Mars brown,” and “dark purplish drab”; others are boldly spotted and blotched with “russet” and “Vandyke brown,” with underlying spots of “brownish drab,” “light brownish drab,” and “light vinaceous-drab.” Speckled eggs are commoner than the more boldly blotched type. The markings are usually concentrated at the large end, and on some of the heavily spotted eggs there is a solid wreath of different shades of russet and drab. The measurements of 50 eggs average 17.2 by 13.3 millimeters; the eggs showing the four extremes measure 18.8 by 13.7, 17.9 by 14.7, 15.7 by 12.7, and 16.3 by 12.2 millimeters (Harris).]
Young.—Cordelia J. Stanwood (MS.) speaks of the nestlings a few days from the egg as “very dark gray, much like young juncos and Nashville warblers.” But when they leave the nest they are clearly recognizable as young black-and-white warblers, although they are slightly tinged with brownish. By mid-July, here in New England, they assume their first winter plumage, and, as both sexes of the young birds have whitish cheeks, they resemble very closely their female parent.
Unlike the young of some of the other warblers which remain near the ground for many days, the young black-and-white warblers shortly ascend to the branches of trees where they are fed by the old birds.
I find no definite record of the length of the incubation period, but in a nest I watched in 1914 it was close to 10 days. Burns (1921) gives the period of nestling life as 8 to 12 days.
Plumages.—[Author’s Note: Dr. Dwight (1900) calls the natal down mouse gray, and describes the juvenal plumage as follows: “Above, wood-brown streaked with dull olive-brown, the upper tail coverts dusky; median crown and superciliary stripe dingy white. Wings and tail dull black, edged chiefly with ashy gray, the tertiaries (except the proximal which is entirely black) broadly edged with white, buff tinged on the middle one. Two buffy white wing bands at tips of greater and median wing coverts. The outer two rectrices with terminal white blotches of variable extent on the inner webs. Below, dull white, washed on the throat and sides with wood-brown, obscurely streaked on throat, breast, sides and crissum with dull grayish black.”
A postjuvenal molt begins early in July, involving everything but the flight feathers; this produces in the young male a first winter plumage which is similar to the juvenal, but whiter and more definitely streaked. “Above, striped in black and white, the upper tail coverts black broadly edged with white; median crown and superciliary stripe pure white. The wing bands white. Below, pure white streaked with bluish black on sides of breast, flanks and crissum, the black veiled by overlapping white edgings; the chin, throat, breast and abdomen unmarked. Postocular stripe black; the white feathers of the sides of the head tipped with black.”
The first nuptial plumage is acquired by a partial prenuptial molt in late winter, which involves a large part of the body plumage, but not the wings or the tail. “The black streaks of the chin and throat are acquired, veiled with white, and the loral, subocular and auricular regions become jet-black. The brown primary coverts distinguish young birds and the chin is less often solidly black than in adults.”
The adult winter plumage is acquired by a complete postnuptial molt, beginning early in July. It differs from the first winter dress "in having the chin and throat heavily streaked with irregular chains of black spots veiled with white edgings, the wings and tail blacker and the edgings a brighter gray. * * * The female has corresponding plumages and moults, the first prenuptial moult often very limited or suppressed. In juvenal dress the wings and tail are usually browner with duller edgings and the streaking below obscure. In first winter plumage the streakings are dull and obscure everywhere, a brown wash conspicuous on the flanks and sides of the throat. The first nuptial plumage is gained chiefly by wear through which the brown tints are largely lost, the general color becoming whiter and the streaks more distinct. The adult winter plumage is rather less brown than the female first winter, the streaking less obscure and the wings and tail darker. The adult nuptial plumage, acquired partly by moult, is indistinguishable with certainty from the first nuptial.”]
Food.—McAtee (1926) summarizes the food of the species thus:
In its excursions over the trunks and larger limbs of trees the Black and White Creeper is certainly not looking for vegetable food, and only a trace of such matter has been found in the stomachs examined. The food is chiefly insects but considerable numbers of spiders and daddy-long-legs also are eaten. Beetles, caterpillars, and ants are the larger classes of insect food, but moths, flies, bugs, and a few hymenoptera also are eaten. Among forest enemies that have been found in stomachs of this species are round-headed wood borers, leaf beetles, flea beetles, weevils, bark beetles, leaf hoppers, and jumping plant lice. The hackberry caterpillar, the hackberry psyllid, an oak leaf beetle Xanthonia 10-notata, and the willow flea beetle, are forms specifically identified. Observers have reported this warbler to feed also upon ordinary plant lice, and upon larvae of the gypsy moth.
Forbush (1929) adds the following observation: “The food of this bird consists mostly of the enemies of trees, such as plant-lice, scale-lice, caterpillars, both hairy and hairless, among them such destructive enemies of orchard, shade and forest trees as the canker-worm and the gipsy, brown-tail, tent and forest tent caterpillars. Wood-boring and bark-boring insects, click beetles, curculios and many other winged insects are taken. Sometimes when the quick-moving insects escape its sharp bill, it pursues them on the wing but most of its attention is devoted to those on the trees.”
H. H. Tuttle (1919), speaking of the male parent feeding the young birds, says: “The fare which he provided was composed entirely of small green caterpillars, cut up into half-lengths.”
Behavior.—The black-and-white warbler seems set apart from others of the group, perhaps because of its marked propensity for clambering over the trunks of trees and their larger branches. Although, like other warblers, it seems at home among the smaller twigs, it spends a large part of its time on upright surfaces over which it moves easily and quickly, upward, downward, and spirally, with great agility and sureness of footing, constantly changing direction, and not using the tail for support. As it scrambles over the bark, it switches from side to side as if at each hop it placed one foot and then the other in advance, and even on slim branches it hops in the same way, the tail alternately appearing first on one side of the branch and then on the other; it reminds us of a little schoolgirl swishing her skirt from side to side as she walks down the street. The bird is alert and watchful, and if it starts an insect from the bark, or sees one flying near, it may pursue it and catch it in the air.
H. H. Tuttle (1919) describes an extreme example of behavior simulating a wounded bird. He says: “She struck the leaves with a slight thud and turned over on her side, while