NATURE NOTES 277 



mutation, that is, a sudden variation, and without any regard to their 

 possible use in defence. This latter on this view is secondary and 

 incidental and the species might have been preserved, as have many 

 others, without such defences. This is quite a different thing from 

 regarding the thorns as of great importance in the struggle for exist- 

 ence. • 



Gypsy Moth Parasites. The law regulating the importation of new 

 species of animals has been temporarily suspended by the Secretary of 

 Agriculture in the case of specimens for study and experiments by the 

 Superintendent for Suppressing the Gypsy and Brown Tail Moths. 

 Another attempt will be made to find a parasite able to control these 

 exceedingly noxious insects. 



What Kills the Birds. E. H. Forbush, Ornithologist of the Massa- 

 chusetts State Board of Agriculture, writes in a special report that 

 the principal natural enemies of birds are cats, foxes, crows, English 

 sparrows, hawks, jays, owls, weasels, skunks, snakes, pheasants, 

 minks, orioles, chipmunks, raccoons and the elements. 



The detructiveness of the cat is noted not only by the greatest num- 

 ber of observers, but, with remarkable unanimity; nearly all who re- 

 port on the natural enemies of birds place the cat first among de- 

 structive animals. Cats in good hunting grounds average at least fifty 

 birds, each, a year. Cats are also more destructive than other 

 animals, because so much more abundant. A friend who was raising 

 pheasants was obliged to kill over two hundred cats in a few years. 

 Game birds suffer much from the cat, but the smaller birds suffer 

 more. Cats are far more destructive to birds than foxes are, for cats 

 climb trees and take the young out of the nests. They easily catch 

 young birds which are just learning to fly. They frequently catch the 

 adult birds on the ground when they are feeding, or when they are 

 drinking or bathing. 



The most harmful characteristic of the cat is its tendency to revert 

 to a wild state. If a dog loses its master and can not find its home, 

 it seeks to form the acquaintance of a new master; but the cat is 

 quite as likely to take to the woods and run wild. It then becomes 

 a terror to all living things which it can master. Whoever turns out 

 or abandons a cat or a kitten in the country has much to answer for. 



Proofs of the destructiveness of cats are not wanting. They were 

 introduced on Sable Island, off the coast of Nova Scotia, about 1880. 

 They ran wild, and, multiplying rapidly, exterminated the rabbits 

 which had been in possession of the island for half a century. 



On Aldabra island, about two hundred miles northwest of Mada- 

 gascar, cats are common. They have decimated the birds, and have ex- 



