Читать книгу Nests and Eggs of Birds of The United States - Gentry Thomas George - Страница 7

The Redwing Blackbird is found throughout North America, from ocean to ocean, and westward to the 57th parallel. From Texas and Florida to the plains of the Saskatchewan, wherever found, it breeds more or less abundantly.

During the winter they congregate in large parties in Southern Virginia, the Carolinas, and all the Gulf States, especially near the sea-coast and among old fields of rice and grain. Occasionally, small flocks are found during the same season about stables and hay-stacks, in the vicinity of Vancouver. But in the Eastern, Middle, Western and Central sections, they are chiefly migrants.

Early in March these large assemblies break up, a part separating in pairs and remaining among the Southern swamps, while the greater portion, the males leading the way, direct their movements northward. Later in April they have re-established themselves in their favorite and accustomed haunts.

On their arrival, the males consort together in high open fields, where their songs may be heard, at regular intervals, from morning until night. At this time they are rather suspicious, and can be approached only by the exercise of great caution. But when the females make their appearance, their attention becomes so absorbed, that they are apparently oblivious of events transpiring around them. The presence of the latter is the signal for redoubled vigor in the line of music. From bush and tree, from ground and fence-rail, and from almost every available place, in loud, clear and resonant notes, is heard their strange, unmistakable melody, each bird striving to outsing his companions. Ever and anon a half-dozen voices may be heard at the same time, producing a perfect medley of sounds, enough to "split the ears of the very groundlings." The males seem never to weary of singing. It is a remarkable and well-authenticated fact, that during the breeding-period, and even late in September when preparing to migrate, the same sweet but pensive strains are heard.

Nearly three weeks have expired since the advent of the Redwing, and still the sexes remain unmated. This cannot long continue. Already a change is manifest. The males are more musical, while, on the other hand, a spirit of restlessness pervades the females. The latter are now no longer given to feeding as before, but cease from their labors, and bend listening ears to the gushing notes of love which swell around. Enraptured, impressed, they eventually emerge from their hiding-places, select their partners, and hie away to more congenial scenes.

The period of mating is unusually short, and unmarked by any special peculiarities. It generally occurs about the 20th of April, but seldom later than the beginning of May. The chief concern of the newly-wedded pair now seems to be the selection of a building-spot. This is a matter of importance, and, with most species, is attended with considerable difficulty. Not so in the present instance. The birds repair to accustomed sites, and there, amid the small bushes and tussocks which abound, prepare their houses.

Nest-making commences in the Middle Atlantic States between the 25th of April and the 1st of May; in New England, about the 1st of June, but not before the middle of this month, in more northern regions. The nest is usually placed in a cluster of reeds, or in the tops of small bushes alongside of streams of water. Occasionally, small trees and fields of timothy are made the recipients of these marks of attention, and, in rare instances, the bare ground is made subservient to this purpose. Almost every ornithologist who has paid any attention to field-work has observed nests in their ordinary positions upon small hushes, or in bunches of swamp grass, but few, we opine, have met with them elsewhere. Mr. Maynard, as stated by Dr. Brewer, seems to have been the first to notice this change. While exploring an island in the marshes of Essex River, he found a number of nests in trees at an elevation of twenty feet from the ground. One of these structures, which was purse-shaped, was composed entirely of eel grass, and placed upon a sapling, at a height of fourteen feet.

High grounds are seldom chosen for nidificating purposes, for the obvious reason that they offer poor facilities for food-collection; the aquatic larvæ, may-flies, dragon-flies, and mosquitoes, which constitute a conspicuous part of the diet of these birds, being only found in marshy situations. Even here a preference is manifested for certain positions. Small bushes along the borders of streams, from the two-fold advantages which they possess, are almost wholly adopted in some localities. Being convenient to appropriate food-stuffs, they are placed beyond the reach of snakes, particularly water snakes, which have a decided partiality for young birds.

Having selected a building-spot, the pair proceed with all possible dispatch to construct a home. This requires the joint labor of the sexes, during the early mornings and evenings, for a period of about five days. The articles of composition are chiefly collected by the male, while the female performs the more difficult operation of putting them in position. Considerable differences are often noticeable in these structures. Those placed upon bushes are, as a general thing, more symmetrical and compact than those found in clumps of grasses, and differ still further in being-plastered with mud on the outside, which adds to their durability; while, on the other hand, nests enclosed by tall overarching grasses, have a looseness of arrangement that will scarcely bear manipulation. But where the nest is placed in fields of timothy and clover, there is evidence of great pains having been taken in its construction.

Having finished their domicile, generally on the following day, but sometimes not for nearly a week afterwards, as is the case when mud and other damp substances have been used in building, the female begins to deposit her eggs, at the rate of one a day, until the full number of five has been laid. Incubation follows on the day of the last deposit, and continues for fifteen days. This business devolves wholly upon the female. While she is thus engaged, the male is not idle, but stands guard over the nest, or ventures off in quest of food for himself and companion. Should the nest be assailed, both parents seek, by the most piteous cries and remonstrances, to drive, off the offending party. In case of pillage, they keenly feel the injustice, and for several days bewail their misfortune. But they soon recover their usual spirits, and prepare to remedy the disaster. So tenacious are they of a chosen locality, that the same pair has been known to build as many as three nests in the same bush, after having been robbed twice.

The parents show the most intense affection for their progeny. Day after day they watch over their helpless infancy with a devotion somewhat akin to that which a human mother manifests toward her child. Their slightest desire is a law, which is obeyed with cheerfulness and alacrity. When food is in demand, they prove themselves to be willing providers, each parent vying with the other in patience and fidelity. While one is absent in quest of food, the other remains at home to protect them from danger, the labor being accomplished by turns. Earthworms, caterpillars, fresh-water larvæ, flies and mosquitoes constitute their earliest fare. But later, beetles, butterflies, and various kinds of fruits help to swell their hitherto very extensive dietary. When about fourteen days old, the young leave the nest, but are not yet prepared to earn their own living. This requires an additional period of twelve days. Brood-raising being over, both young and old continue in the old haunts, until near the time of departure, when they collect in small flocks, and take up their southward-bound journey.

A typical nest of this species is somewhat irregular in shape, and rather coarsely and rudely built. It is composed of stubble and broad grasses variously intermingled, and lined with soft meadow grass. The dimensions vary according to locality. Several nests before us, from New Jersey, Pennsylvania, and the South and West, have an average external diameter of five inches, and a height of three. The cavities, however, are more uniform, and generally measure three inches in width, and one and a half in depth. But when a nest is built in a bush, the outer basketlike frame is carefully interwoven with, and strongly secured to, adjacent twigs. Though somewhat rudely put together, it is nevertheless firmly and compactly woven. The outer framework is usually made of rushes, strong leaves of the iris, and, in some instances, of an additional article apparently similar to mud. Within is packed a mass of coarse materials, over which is placed a thick lining of grasses and sedges. These nests, in the matter of size, differ from the former chiefly in the particulars of length and thickness. The internal dimensions offer no very striking exceptions.

The nest represented in the Plate is three-fourths of the natural size, and was obtained by the writer in the summer of 1879, by purchase, from Mr. Alexander M. Reynolds, of Philadelphia. It was built in a field of grass, many of the stalks of which being wrought in its composition. In figure it resembles an inverted cone, and is beautifully, symmetrically and compactly put together. The outside is formed of grasses and rushes, very neatly and intricately interwoven, and shows here and there a head of dried pappus plucked from some species of hawkweed. The inside is lined with sedges and fine blades of grass. As shown in the drawing, the nest occupies a rather conspicuous position. This was not the case in its natural location. Being found in the centre of a large field, it is at once evident that the authors had spared no pains to make the concealment as complete as possible. In height, this fabric measures nine inches. Its external diameters above, below, and in the middle, are, respectively, six, two, and four and a half inches. The width of the cavity is three inches, and the depth three.

The eggs are oval in contour, of a light bluish ground-color, and are marbled, blotched and streaked with light and dark purple, chiefly about the greater extremity. In size, they vary considerably; the average length of a large number of specimens from different regions being 1.01 inches, and breadth .76. In the Middle, New England and Western sections of our country, this species is single-brooded; but further south, three, and even a larger number of broods, are annually raised.