Читать книгу Nests and Eggs of Birds of The United States - Gentry Thomas George - Страница 11

The Red-eyed Vireo is quite an abundant species throughout Eastern North America, ranging from Florida in a northeasterly direction to Nova Scotia, thence northwesterly to Lake Winnipeg and Washington Territory, and westerly to Ogden, Utah. Accidental specimens have been procured in Greenland and England, but never more than a single individual in each locality.

Many of these birds winter in Florida, and as specimens have been met with in Central America, Cuba, Trinidad, and on the Isthmus of Panama, it is highly probable that many betake themselves thither when the period of breeding is over in their northern homes.

Early in March the latter enter the United States, possibly by way of Texas and Florida, and wend their movements northward, reaching the Middle States late in April; the New England, about the middle of May; and the extreme northwest, a fortnight later.

Like all of its peculiar and characteristic genus, this species affects a fondness for forests, or the summits of tall trees, but seldom ventures upon the ground. It is, however, not wholly sylvan. At times it may be found around dwellings, or along the shaded streets of rural towns, in quest of the various insects which contribute to its sustenance.

As it gleans among the tree-tops, the simple, pleasing and musical notes of the male may be heard at somewhat regular intervals. So unsuspicious and familiar is he then, that passers-by may come and go, and their presence be unheeded.

During the hot and sultry hours of noon when other songsters have ceased their warblings and foraging, and have slunk to the refreshing shades for comfort and security, our little friend continues to pour forth in loud, sonorous notes his peculiar te-te-tu'eah-we-ah-tweah-tweah-tweet. Being the earliest of our vernal choristers, he is also the most constant and untiring, and continues to sing throughout the entire season. Even when about to depart for the smiling scenes of his southern home, he thrills the air of woodland and valley with impassioned song.

His tender and pathetic utterances, which resemble the melodious notes of the Robin, but lacking their volume and power, are produced with so much apparent animation, judging from their sound, as to be in striking; contrast to the seeming indifference or unconsciousness of the plain little vocalist who, while regaling the listener, appears all the while to be bent upon the procurement of his daily food, which he pursues with great ardor. But with the female the case is different. Although quite as active a feeder as the male, yet there is apparent none of that bustle and noise which characterize his movements. Her chief concern seems to be the satisfaction of hunger, and a studious avoidance of the male.

But as the days multiply, and insect life becomes more common, which is generally the case about two weeks after their arrival, less anxiety is felt on account of food; consequently, more time is left for the development and play of the social forces. The sexes now begin to manifest less reserve and coolness, and instead of shunning each other, as was their wont, are brought more and more into friendly intercourse. A week or ten days later, and the way is paved for the assumption of matrimonial relations. In this movement, the male takes the lead. The female, somewhat coy, at first listens to the wooings of her suitor at a wary distance, but as time progresses, soon learns to regard him in the light of a lover, throws off her restraint, and confidently advances to receive his caresses. And thus events follow each other in rapid succession until a union is effected.

Having mated, the happy pair, with no more delay than is absolutely necessary, start off together in search of a nesting-place. This is a matter that is easily accomplished, as almost any forest-tree of small or medium height, answers the purpose. In some situations, the beech, maple, sassafras and common laurel are in special demand. Why this is so, it is impossible to divine.

High woods, with an abundance of small trees, are generally chosen. Here, the nests are not often placed higher than five or six feet above the ground. Sometimes, though rarely, they are found swinging from a pendent bough, more than fifty feet high. Nidification seldom occurs in compactly-built cities. Never more than a single instance has ever been observed by us. This happened in the summer of 1876.

A site being chosen, building at once commences. This occurs in the Middle States between the twelfth of May and the fifteenth of June; in New England, about the first of the latter month; in Texas and Louisiana, somewhat earlier; and in Nova Scotia, a trifle later. At Fort Resolution, at the Cumberland House, and at Fort Simpson, nests and eggs have been taken, but we are left in ignorance as to the time.

The construction of a home is the result of the united labors of both birds, each collecting and adjusting its own materials. The time devoted thereto varies from six to seven days, and is regulated by the industry of the builders and the condition of the weather. For this purpose a bifurcated branch is first chosen. To this is attached, by means of cobwebs, strips of bark, threads of moss, and the silk of caterpillars, a delicate framework. This is mainly composed of bark, decayed pine-wood, vegetable fibres, etc., held together by silk, and, possibly, in a slight degree, by a gummy secretion supplied by the builders. This structure is long, tenuous, open and narrow, presents a somewhat collapsed appearance, and resembles, though remotely, the perfect fabric. But it lacks shape and symmetry. To give it these essentials, the birds construct an inner nest out of bits of paper, fragments of hornets' nests, and strips of oak bark, which are so arranged as to protrude through the interstices of the outer. It is now the duty of the female, by a few bodily evolutions, to reduce the whole to form. This accomplished, the labor of building is resumed, and a cozy lining, composed of narrow strips of the inner bark of the wild grape-vine, is added. Often white and black horse-hairs take the place of these articles. That this species builds after the fashion described, is proved by actual observation, and also by the finding of abandoned nests which showed the outer, but not the inner arrangement.

The nest represented in the Plate came from Atlantic Co., N. J. It was built between a forked branch of the common laurel. Externally, it is composed of decayed wood, inner bark of plants, silk of caterpillars, fragments of hornets' nests, cocoons of spiders, etc. Internally, there is a thick lining of the inner bark of the wild grape-vine. The external diameter is three and a half inches; internal, two and a half inches; outside depth, two and a quarter, and inside, one and three-fourths inches. A comparison with specimens from Texas, Michigan, Pennsylvania and Massachusetts, shows marked similarities in structure and details of composition.

In the collection of the Smithsonian Institution there is to be seen a nest which was obtained by Mr. Kennicott at the Cumberland House, on the Saskatchewan River. It is pensile, like all others, but is almost exclusively built of pine-needles – a dry and hard material, difficult of management in the construction of such a domicile. With these are intermingled flax-like vegetable fibres, fine strips of bark, and fragments of moss. Within is placed an inner nest composed of strips of bark, pine leaves and fine, dry grasses. The external fabric is rather loosely put together – an unusual feature – but the inner portion, in the compactness and strength with which it was made, is in striking contrast.

After the nest is finished, the female, on the ensuing day, and occasionally not until the expiration of the third or fourth, commences to lay her eggs, at the rate of one daily, until the entire complement of three or four has been laid. Incubation follows closely, usually on the day succeeding the last deposit, and continues for nearly eleven days. This is not the exclusive task of the female, as the male sometimes assists her. When the latter is not thus occupied, it is seldom that he may be found in the vicinity, being absent either designedly, or in search of food. Should the nest be approached at this time, the female sits close, and seems to manifest neither timidity nor alarm. We have often surprised her on the nest, and reached out our hand to take her, when she would watch our actions very narrowly, as if seeking to study our motives, but remaining perfectly motionless all the while. A nearer approach was invariably followed by her sudden departure therefrom. The bird would not wholly desert the nest, but demurely station herself upon an adjoining twig, in order to watch our actions. But with the male it is quite different.

Any attempt at disturbance or pillage is resented with spirit and courage, especially when the nest contains young birds.

The home of this Vireo is often chosen by the Cowbird as a place of deposit for her eggs. So singularly devoted to their alien guests do these foster-parents become, that they nurture them very tenderly, even to the neglect of their own offspring. A case is mentioned where three of these parasitic eggs had been deposited in the nest of the Vireo before any of her own. Without laying any, the female Vireo proceeded to set upon and hatch the intruders. Another case is cited where two Cowbird's eggs were laid alongside of two of the Vireo's. The latter immediately stopped laying and proceeded to incubate. In each of these cases it is evident that the female Vireo forewent her own maternal instincts, and at once conformed to the new situation.

The young are objects of special parental interest. From the time they are hatched, until the period of their leaving the nest to earn a livelihood, they are watched over, and fed with the daintiest fare which Nature affords. Caterpillars, diptera, plant-lice, small spiders and berries, constitute their earliest diet; but as they increase in size and strength, other articles of a coarser nature are added. At the age of twelve days they vacate the nest, but continue under the watchful eyes of their parents a week longer, when they are able to forage for themselves.

The anxieties of brood-raising being over, both young and old, the former in imitation of their parents, seek the tall tree-tops and glean in company. Later, they come down from these lofty retreats to delve among the grasses. Finally, as if disdaining too near an approach to earth, they quickly forsake such groveling pursuits, and seek the viburnum and dogwood bushes, where they find many a rich repast. Here they remain until the last of September, or the beginning of October, when cold weather and scarcity of food compel them to hunt warmer climes.

The eggs of this Vireo vary considerably in size, according to locality; the further south the smaller they are found. Specimens from Northern Alabama have an average measurement of .77 of an inch by .52; from Nova Scotia,94 by .65; from Pennsylvania and Massachusetts, intermediate localities,82 by .56, and .83 by 62. The ground-color of all is a clear crystal-white, and they are marked with spots and fine dots of red-brown, which are chiefly found at the larger extremity. But a single brood is raised, although nests with eggs have been taken early in July, which must be attributed to birds whom accident or design had prevented from obeying their natural instincts earlier.