Page:Popular Science Monthly Volume 11.djvu/605

This page has been validated.
587
INSTINCT AND INTELLIGENCE.

such time as some of our company did fire upon them, whereby they were rendered more shy.' Dampier also, in the same year, says that a man in a morning's walk might kill six or seven dozen of these doves. At present, although certainly very tame, they do not alight upon people's hats, nor do they suffer themselves to be killed in such large numbers. It is surprising that they have not become wilder; for these islands, during the last hundred and fifty years, have been much visited by buccaneers and whalers; and the sailors, wandering through the woods in search of tortoises, take a cruel delight in knocking down the little birds."

Darwin also says that at Terra del Fuego a certain species of goose, which is much hunted by the natives, is so wild that it is a very difficult matter to kill even one, although in the Falkland Islands, where it is not often disturbed by man, a sportsman may sometimes kill more in a day than he can carry home. This goose is not migratory; but a bird of passage, the black-necked swan, brings with it to the Falkland Islands the wisdom learned in more dangerous regions, and is very hard to obtain. Darwin ends with the following comments: "From these several facts we may, I think, conclude, first, that the wildness of birds with regard to man is a particular instinct directed against him, and not dependent on any general degree of caution arising from other sources of danger; secondly, that it is not acquired by individual birds in a short time, even when much persecuted, but in the course of successive generations it becomes hereditary. With domesticated animals we are accustomed to see new mental habits or instincts acquired, and rendered hereditary; but with animals in a state of nature it must always be most difficult to discover instances of acquired hereditary knowledge. In regard to the wildness of birds there is no way of accounting for it except as an inherited habit; comparatively few young birds, in any year, have been injured by man in England, yet all, even nestlings, are afraid of him; many individuals, on the other hand, both at the Galapagos and at the Falklands, have been pursued and injured by man, but yet have not learned a salutary fear of him." If instincts have been acquired gradually by natural selection—like modifications of structure—we should expect to find that, like other adaptations, they are in many cases more or less imperfect. We were formerly taught that instinct differs from intelligence inasmuch as it is an infallible guide and perfect in its results. If we have shown that it admits of improvement, we need not argue its imperfection; but a few examples of the failure of instinct may not be out of place. Migratory birds often return too early in the season, and perish from lack of food. The instinct which leads insects to lay their eggs upon or near food which is proper for the larvæ to which the eggs will in time give rise, although the adult insect may feed upon something quite different, is a very wonderful and beautiful