Page:Popular Science Monthly Volume 77.djvu/143

Rh crow in Egypt and India, where from a long and undisturbed intercourse with man, it has come to build its nests in the city streets, and in Cairo even before the foliage of the lebbek trees is out, often gives free rein to this propensity, as was well shown by the experience of an optician in Bombay, who lost a large store of steel spectacle-frames, and later found them in a ruined state, worked into a nest of this familiar bird. The propensity to seize bright objects, and to hide and store food by burying it in the ground, a practise attributed to the European crow, raven, magpie and rook, is undoubtedly instinctive in origin. Their ability to find it' again would depend more upon intelligence than in the dog, which has the same tendency, for they are presumably without the guiding power of scent. The Californian woodpecker (Melanerpes formicivorus) is noted for the autumnal stores of acorns which it embeds in the bark of trees, but the strong instinctive impulse which shapes its conduct is accentuated by the reported fact that the holes so nicely drilled are occasionally filled up with stones.

That color plays an important part in the lives of birds seems highly improbable, although it is a commonplace fact that the nest in many cases harmonizes perfectly with its surroundings. For several seasons I made a practise of offering colored yarns, such as blue, brown, green and bright red, to various species of birds, for building purposes, and especially to robins and cedar waxwings; as a rule, all colors were taken indiscriminately, with very bizarre nests as a result. When white threads or long streamers of cotton cloth were added, these were usually taken first, and in greater quantity, apparently because they were more conspicuous, and sometimes to the detriment of the builders. Thus, one of the least flycatchers took and dropped so much of the cloth that a white trail was finally laid from field to nest, in the construction of which five times more was used than needed. The quaint structure which resulted was too obvious to escape destruction, and it did not endure many hours.

The docility of birds is well illustrated by the trainer's power over many species, and by the tricks which, through a system of rewards and punishments, they can be made to perform. A classical illustration is furnished by the art of falconry, the popular sport of middle-age Europe, in which the young of the wild peregrine falcon, or of some other hawk, was trained to limit its instinct to kill to a particular kind of game, to follow the falconer afield, to stoop to the quarry, and return to its master's call. After a similar fashion the instincts of the cormorant have been molded to the will of man, and successfully used in taking fish, a practise which I am informed may still be witnessed in certain remote fishing communities in Japan, the trained birds descending from father to son.

Modern experiments in the laboratory, which have been conducted