It is quite otherwise with the habitat of the quadruped. He comes into the world clothed; what need has he of a nest? Thus, then, those animals which build or burrow labour for themselves rather than for their young. A skilful miner is the mountain rat, in his oblique tunnel, which saves him from the winter gale. The squirrel, with hand adroit, raises the pretty turret which defends him from the rain. The great engineer of the lakes, the beaver, foreseeing the gathering of the waters, builds up several stages to which he may ascend at pleasure; but all this is done for the individual. The bird builds for her family. Carelessly did she live in her bright leafy bower, exposed to every enemy; but the moment she was no longer alone, the hoped for and anticipated maternity made her an artist. The nest is a creation of love.
Thus, the work is imprinted with a force of extraordinary will, of a passion singularly persevering. You see in it especially this fact, that it is not, like our works, prepared from a model, which settles the plan, conducts and regulates the labour. Here the conception is so thoroughly in the artist, the idea so clearly defined, that, without frame or carcase, without preliminary support, the aerial ship is built up piece by piece, and not a hitch disturbs the ensemble. All adjusts itself exactly, symmetrically, in perfect harmony; a thing infinitely difficult in such a deficiency of tools, and in this rude effort of concentration and kneading by the mere pressure of the breast. The mother does not trust to the male bird for all this; but she employs him as her purveyor. He goes in quest of the materials—grasses, mosses, roots, or branches. But when the ship is built, when the interior has to be arranged—the couch, the household furniture—the matter becomes more difficult. Care must be taken that the former be fit to receive an egg peculiarly sensitive to cold, every chilled point of which means for the little one a dead limb. That little one will be born naked. Its stomach, closely folded to the mother's, will not fear the cold; but the back, still bare, will only be warmed by the bed; the mother's precaution and anxiety are, therefore, not easily satisfied. The husband brings her some horse-hair, but it is too hard; it will only serve as an under-stratum, a sort of elastic mattress. He brings hemp, but that is too cold; only the silk or silky fibre of certain plants, wool or cotton, are admissible; or better still, her own feathers, her own down, which she plucks away, and deposits under the nursling. It is interesting to watch the male bird's skilful and furtive search for materials; he is apprehensive lest you should learn, by watching him with your eyes, the track to his nest. Frequently, if you look at him, he will take a different road, to deceive you. A hundred ingenious little thefts respond to the mother's desire. He will follow the sheep to collect a little wool. From the poultry-yard he will gather the dropped feathers of the mother hen. If the farmer's wife quit for a moment her seat in the porch, and leave behind her distaff or ball of thread, he will spy his opportunity, and go off the richer for a thread or two.
Collections of nests are very recent, not numerous, and, as yet, not rich. In that of Rouen, however, which is remarkable for its arrangement; in that of Paris, where many very curious specimens may be examined; you can distinguish already the different industries which create this master-piece of the nest. What is the chronology, the gradual growth of it? Not from one art to another (not from masonry to weaving, for example); but in each separate art, the birds which abandon themselves to it are more or less successful, according to the intelligence of the species, the abundance of material, or the exigency of climate.
Among the burrowing birds, the booby, and the penguin, whose young, as soon as born, spring into the sea, content themselves with hollowing out a rude hole. But the bee-eater, the sea-swallow, which must educate their young, excavate under the ground a dwelling which is admirably proportioned, and not without some geometrical design. They furnish it, moreover, and strew it with soft yielding substances on which the fledgling will be less sensitive to the hardness or freshness of the humid soil.
Among the building-birds, the flamingo, which raises a pyramid of mud to isolate her eggs from the inundated earth, and, while standing erect, hatches them under her long legs, is contented with a rude, rough work. It is, moreover, a stratagem. The true mason is the swallow, which suspends her house to ours.
The marvel of its kind is, perhaps, the wonderful carpentry which the thrush executes. The nest, very much exposed under the moist shelter of the vines, is made externally of moss, and amid the surrounding verdure escapes the eye; but look within: it is an admirable cupola, neat, polished, shining, and not inferior to glass. You may see yourself in it as in a mirror.
The rustic art, appropriate to the forests, of timber-work, joining, wood-carving, is attempted on the lowest scale by the toucan, whose bill, though enormous, is weak and thin: he attacks only worm-eaten trees. The woodpecker, better armed, as we have seen, accomplishes more: he is a true carpenter; until love inspires him, and he becomes a sculptor.