616 THE POPULAR SCIENCE MONTHLY. 



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 wonder- 

 ful 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 na- 

 tive 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 per- 

 ceptions 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, com- 

 pletely shows. Mr. Leith Adams bears witness to this, and tells be- 

 sides the story of the trick played by the ruby-throated humming- 

 bird 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, constant- 

 ly feign sleep, for the purpose of catching birds or mice more effectu- 

 ally. 



