Читать книгу Nests and Eggs of Birds of the United States - Thomas G. Gentry - Страница 12

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The Wood Pewee, like most of its congeners, has a somewhat extended habitat, ranging from the Atlantic westward to the Plains, and from Texas to New Brunswick. It visits the United States about the 15th of April, and from this time until its departure for Guatemala in October, it is principally an occupant of high-wooded regions with a scanty growth of underbrush, and timbered river-bottoms.

But as the season advances, and the amatory feelings become awakened, these shady retreats are deserted by a few individuals of more venturesome disposition, and a temporary abiding-place is sought for amid the stirring scenes of active farm-life. This generally occurs during the last of May or the beginning of June, and is the prelude to the more important act of mating, which follows.

The assumption of matrimonial relations, however, is not a matter that is entered into without more or less consideration. Occasionally, much time is spent in its preparation. This is presumably the case when a young female is courted by some venerable male. But when an apparently experienced individual is the object of his devotion, the state of things is different. His advances are then either encouraged and reciprocated, or they are declined, and the disappointed suitor compelled to seek a partner elsewhere. It is probable, moreover, that the same birds pair together on each return of the breeding-season, unless prevented by death, or some other of the numerous vicissitudes of life.

The ceremony of mating being over—which business is ordinarily of short continuance, seldom lasting for a greater period than two days—the newly-wedded pair now set out to discover a suitable place for the building of a home. This is a matter of considerable moment, often requiring the performance of long and extended tours of observation and exploration. These reconnoissances generally last for a week, but eventually result in the choice of a locality well adapted, as far as the essential conditions of shelter and security are concerned, to become the depository of a nest. The site generally chosen for this important purpose is a tall open woods with a preponderance of ash or oak trees; but where a time-honored orchard is the recipient of this favor, which is sometimes the case, the apple, 011 account of the many advantages which it possesses, is preferred above all other fruit-trees.

The site being mutually agreed upon, the happy pair proceed with all possible dispatch and diligence to construct a domicile: the male to collect and bring in the necessary materials; the female, to fix them in their proper places, and also to give shape and symmetry to the structure. The time devoted to this work varies with the industry of the builders, the style of the nest, and the character of the neighborhood. But, where the birds are laboring under the most favorable circumstances, the task is easily accomplished in five days.

This admirable piece of bird-architecture, which rivals in beauty and symmetry the nest of our little Ruby-throated Humming-bird, is either saddled upon a living or dead limb that is horizontal and lichen-clad, or else upon the crotch of a bifurcated branch, and is placed above the ground at elevations varying from five to thirty feet. According to Nutt all, "the body of the fabric" occasionally consists of "wiry grass or root fibres;" but we have yet to meet with a nest with "small branching lichens held together with cobwebs and caterpillars' silk, moistened with saliva," as that author remarks. In a structure before us, which is typical in its character, small strips of inner bark plucked from trees of chestnut and oak, bits of tow, and fragments of wool, circularly arranged and compactly pi-essed together, are the prevailing constituents. Externally, it is closely invested with the bluish-gray crustaceous lichens which are so plentiful upon the trunks of certain trees, and also upon fence-rails. In diameter, it measures three and a half inches; in height, one and a half inches. The width of the cavity is about two inches; the depth in the centre, three-fourths of an inch.

The most beautiful fabric, as well as the most compactly built, which we have seen, was obtained in the spring of 1870, not far from Germantown, Pa. It was placed upon a horizontal branch of an apple-tree, in close proximity to a farm-house. Externally, it is thickly covered with bluish-gray crustaceous lichens, which are held in place by a few cobwebs, and fragments of the silk of caterpillars. The base consists of dried stems of grasses, and on these is reared a neat and cosy superstructure composed of the inner fibres of the wild and cultivated species of the vine, and a slight sprinkling of wool. These materials are variously interwoven, and arranged around the margin so as to form a cavity. The dimensions of this nest are as follows: External diameter, three and a half inches; height, one and a half inches; width of cavity, two inches; depth in the centre, three-fourths of an inch. In the Plate it is represented the natural size—built upon an oak branch.

In the details of form and dimensions, this nest differs immaterially from specimens which we have met with and seen from other localities. But wherever obtained, they will always be found to bear a very close resemblance to one another, differing chiefly in the character of the articles which constitute the inner arrangement. We will merely mention one example which was taken by Mr. Welch, in Lynn, Mass., and which will give our readers some faint conception of the extent to which variation is often carried. This structure was placed upon a dead limb of a forest-tree. Its walls were composed of small dry stems and vegetable down, finely interwoven, and covered on the outside with lichens which were cemented to it by a viscid secretion that was apparently supplied by the builders. The base wras somewhat flattened, much thinner than the walls, and composed of finer materials. The external diameter was three inches, and the height one and a half inches; the cavity, two and a half inches at the rim, and the central depth about one inch.

Having finished their home, only a day or so intervenes when oviposition becomes the controlling instinct. The female now proceeds to deposit her complement of four eggs, which she does on consecutive days, at the rate of a single egg daily. This is followed, on the day succeeding the last deposit, by the trying duty of incubation. Upon the female devolves this arduous and irksome labor. For about eleven days she is thus engaged, until her patience is finally crowned with success. Although the male takes no part in this duty, yet he contributes his share to the prosperity of the undertaking, by guarding his partner from danger, and supplying her with the essential articles of food. When his home is assailed by feathered enemies, if they are not more than a match for his strength, he is not slow to wreak instant vengeance upon them. But in the case of human depredators, where effort would be futile, no exertion is put forth to cause desistance from any contemplated assault, save a little scolding.

The eggs are four in number, and resemble in configuration those of the common Phoebe-Bird. They are obtuse at one extremity, and slightly tapering at the other. The ground is a rich cream-color, and is diversified about the larger end with a wreath of purple and lilac spots, which are large, and occasionally confluent. In length, they measure .76 of an inch, and in width .54. It is pretty well established that but a single set is deposited by any given pair of birds in a season. Nests with eggs, however, have been taken during the last of July, or the beginning of August; but whether a second laying or not, we cannot say—possibly the work of birds whose early efforts had been frustrated.