Page:Popular Science Monthly Volume 3.djvu/632

616 which adapted themselves within a few days to the increased range of the rifle, directly after they had learned its range for the first time, having been previously accustomed only to the fowling-piece, and kept just outside the two thousand yards' range, or whatever range it was, retaining their composure perfectly at that distance. We suppose the wonderful accuracy of the travelling birds in striking the exact point for which they are bound, of which Mr. Leith Adams gives us wonderful illustrations, is a still greater proof of the same power. Mr. Adams tells us of swifts which, after eight months' absence in the South—at a distance of some 1,800 or 1,900 miles—return not merely to the same region, but to the same nests which they had deserted, and that, too, year after year—the individuals having been marked so that there could be no mistake as to their identity, unless indeed there be such creatures as claimants to abandoned nests even in the ornithological world. Again, the delicate adaptation of the power of geometrical measurement to the welfare of its species seems to be shown by the weaver-bird of India, which hangs its "elaborately-constructed, purse-shaped nest" "from the tops of branches overhanging deep wells," in order to render it particularly difficult for enemies to get at the nest without running a great risk of falling into the well.

Again, none of the lower animals, except the monkey, seem to have so much imitative power, particularly in relation to sounds—the imitative power of monkeys has more of capacity in it for imitating gestures—as parrots, mocking-birds, ravens, and other tribes of birds. Curiously enough, this seems to be more or less a quality of tame, as distinguished from wild birds. At least, Mr. Leith Adams says that parrots, the cleverest of all these imitators when in captivity, "are not by any means given to copy the call-notes of other birds in their native woods," so that imitation would seem to be the channel into which their intellectual energy is apt to be directed, when they are robbed of their natural occupations. That is, we suppose, their perceptions being very acute, and their voice well developed, directly they are cut off from their usual occupations, they begin to imitate all they hear by way of exercising their latent faculties. That birds can go beyond mere imitation, and are to some extent accomplished actors, the evidence as to all those birds which, by false pretences of agitation, lure the trapper away from the vicinity of their nest, completely shows. Mr. Leith Adams bears witness to this, and tells besides the story of the trick played by the ruby-throated hummingbird of Canada, which, if captured, "feigns death by shutting its eyes and remaining quite motionless," and then suddenly makes a vigorous effort to escape. This shows not merely a dramatic gift, but a distinct purpose in the use of it. Ruses of a similar kind are, however, not unexampled in other animals and birds. Cats, for instance, constantly feign sleep, for the purpose of catching birds or mice more effectually.