When a tree is chosen, the happy pair proceed to build their loose, rickety dwelling upon a forked or horizontal branch, at elevations varying from five to seldom more than twenty feet, according to our experience. The nest may be compared to a miniature Crow's. It is mainly composed of small sticks and some grasses, artlessly and loosely interlaced, and so unsubstantial, that it scarcely survives the season. The cavity is quite shallow. The dimensions vary somewhat with the locality, but a specimen before us measures seven inches in diameter, and about three in height. The cavity is nearly four inches wide, and less than one in depth. The construction of such a loose affair ordinarily requires but two days, and is the result of the united efforts of both birds, working with commendable patience and zeal, but not continuously.
As soon as the domicile is finished, the female, after a day spent in congratulating her lord upon their combined success, proceeds to furnish it. This business continues for many days, varying according to the number of eggs laid, and the irregularity in time of laying, eggs being frequently deposited about the time that others are hatching. Nests are often found with a single fresh egg in each, another partly incubated, a newly-hatched bird, and one or more young still further advanced. But, as a rule, only a single egg is daily deposited. Incubation, in the latitude of Philadelphia, often commences when only two eggs are deposited, but instances are recorded where such was the case after the first extrusion, the female depositing others as the process goes on. This seems like a strange fancy of hers, but evidently shows great forethought and prevision.
The rude house which is built for the accommodation of the eggs, being open and much exposed, and made of seemingly unsuitable materials, fails to provide the necessary protection, and thus is necessitated close and arduous sitting by both birds. The hatching of a few young birds at the time when eggs are being laid, secures the continued warmth necessary for development, and thus materially aids parental exertions. In many instances the eggs are deposited before the incubating process has commenced. The time required for hatching is about fourteen days.
While this business is progressing, the male, when not upon the nest, seldom forsakes his partner, save to provide himself and her with food. Perched upon a small limb close-by, he seems all vigilance, and is in constant readiness to reply to her calls. Feelings of the most devoted affection are mutually exchanged. If the eggs are handled, prior to the assumption of incubation, the birds are apt to desert the nest; but when this has commenced, the female is so attached to her young that she will almost permit herself to be captured rather than leave them. If forced to vacate, we have never known her to precipitate herself upon the ground, and seek, by her fluttering and personation of lameness, to draw the intruder away, as Nuttall affirms, but have always observed her to take a position upon a tree in the immediate vicinity, where she would sit silently and demurely contemplating the purposed desecration. Mr. Newton, in his paper on the habits of the birds of St. Croix Island, testifies to the conjugal affection which is evinced by these birds. On one occasion a male had been killed. The female, attracted by his shriek as he fell to the ground, appeared upon the scene, and showed the most intense anxiety.
In the summer of 1872, a nest of this species was placed upon a tree within full view of our window, from which the minutest details of the every-day life of these birds could be closely studied. Children in their plays would frequently pass under the tree while the birds were engaged in breeding, but the latter were so intent upon the work that their presence was unheeded. The nest was completed, eggs were deposited and hatched, and the young matured, the parent birds evidently feeling as secure as in more retired situations. On this occasion it was discovered that when the young were all hatched together, the duty of feeding devolved upon one or the other parent, both never being absent from the nest at the same time. But, on the other hand, where the young are hatched at irregular intervals, the non-incubating bird assumes the duty of providing nourishment both for his mate and early-hatched young, while the other is occupied with the cares of incubation. When the young are able to quit the nest, which they do in little more than a fortnight after hatching, the parents hail the event with great joy. Their efforts to induce them from the nest at first are rather amusing, and evince extreme patience and thorough good-will. But when the step is once taken, their odd, curious gestures betoken the highest pleasure and satisfaction. The young are now almost old enough to care for themselves.
Never more than a single brood is annually raised in Pennsylvania, although Mr. Nuttall affirms that several are brought out, according to his observations. His opinion appears to have been based upon the discovery of eggs as late as August 28. In some localities this may be so, but we cannot find any record thereof. The same distinguished writer has recorded the finding of a Cuckoo's egg in the nest of a Catbird, and another as late as the fifteenth of July, in a Robin's nest. These were considered at first as rare, if not incredible instances, but latterly, we have some well-authenticated cases of such parasitism. These observations, coupled with others equally as important which have been recorded, tend to show a close relationship between our American Cuckoo and their not very distant European brother.
The eggs of this bird are oblong-oval, less spherical than those of the Black-bill, and have an equal obtuseness at each end. They are of light bluish-green color, and, like those of the other, are quite apt to fade on exposure to light, thus rendering them difficult of distinction. The average measurement is 1.22 inches in length, and .94 in width, although specimens are occasionally found which show marked variations in size, some being smaller, but few exceeding these dimensions.
