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Birds' Nests and Eggs — Part 1

A CAREFUL examination of a bird's nest will convince any one that it is a work of art. One cannot help wondering at the ingenuity displayed by its architect. How carefully a bird adapts itself to environment is well illustrated by endless examples: the red-winged blackbirds (whose nests are usually built among reeds, flags, or bushes) make their nests very much deeper when the place selected is subject to strong winds than in more sheltered spots; and then, as a further safeguard, the mouth of the nest contracts so that the eggs will not fall out when the flags are swayed by the wind. These clever birds have even been known to place their eggs in a deserted woodpecker's nest in places where the fish crows were numerous--for the fish crow is worse even than the jay as an egg and fledgling thief. In this way the redwings managed to elude their persecutors and saved their eggs and young from destruction.

Some birds readily avail themselves of new and favourable conditions. The phoebe formerly built its nest exclusively on rocks, but now that houses and bridges are to be found throughout the country, this bird has to a great extent changed its former custom, and it now build nests on almost any sort of structure erected by man. This also applies to the barn swallow, while the chimney swift has taken possession of our chimneys, and almost forsaken the hollow tree-trunks, in which, but a few years ago, they built in large colonies.

How rapidly birds are changing their habits is not known, but it is evident from the few examples we have about us that a change is progressing, in some cases very noticeably.

Of course a bird's main idea when depositing its eggs is that they shall be safe from enemies of all kinds and from unfavourable weather conditions. With these objects in view it is interesting to note the different methods employed. The whippoorwill builds no nest, but lays its eggs in a slight depression among the dead leaves. When the parent bird is sitting, her colour, which matches the leaves and dead wood, saves her from observation. The eggs themselves are much like either stones or the under sides of leaves, so they are difficult to find even when exposed. But if they are discovered, the parent bird carries them away to a new hiding place. The quail and many other birds, such as the meadow-lark and some of the sparrows, often arch their homes over with either the growing vegetation surrounding the nest, or with dry material brought for the purpose, and in some cases they build covered paths or entrances. The woodpeckers hide their eggs in natural holes in trees, or in holes hollowed out after much tedious labour by the birds themselves; here the eggs are fairly safe; squirrels, snakes, and human beings are about the only enemies to be feared. The crested flycatcher often makes use of a snake-skin in the construction of his nest, which occupies a hole in a tree. It is only reasonable to suppose that there is some object for his preference for this strange and apparently useless material. It may be that it frightens away would-be thieves, squirrels, jays, or crows (for the opening to the nest is often large enough to allow a crow to enter without difficulty); here is a case where authentic observations might tell us much of the bird's life-history.

The ruby-throated humming-bird saddles his tiny nest usually on a high branch, and covers it with lichen so that it resembles an excrescence on the branch. Why the long-billed marsh wren builds so many "dummy" nests, most of which are usually near the real nest, is not known, but it is presumably as a matter of safety, and for the purpose of misleading intruders, just as a parent bird will feign a broken wing to lure danger from the young.

The Baltimore oriole hangs his well-built nest, a masterpiece of bird architecture, on the extreme end of an overhanging branch where nothing but a winged enemy can reach it. To guard against these the nest is made so that it looks something like a hornet's nest--with which the jays, crows, or hawks would not care to interfere. Then, again, after all these precautions, the comfort as well as the safety of the young is thought of when the nest is built, the lower part being compactly and strongly made, while the walls are loosely woven so as to admit of free circulation of air. The eggs of the belted kingfisher are placed in a hole often six or eight feet deep, excavated in a bank by the birds themselves after as much as two weeks' work. One possible reason for the choice of such a place is the fact that the young, which are fed on fish, regurgitate large pellets of scales and bones and such indigestible matter; were these dropped beneath a nest built in a tree or on the open ground it would betray the presence of the home to the natural enemies of the bird. Why the cowbird declines the responsibilities of maternity has never been satisfactorily explained. It is certain, however, that there is some good and sufficient reason.