152 Conservation Reader 



upset Nature's arrangements, and from that time until now 

 matters of this kind have been growing worse. We have 

 killed large numbers of the beneficial animals and birds that 

 kept the harmful ones in check. We have carried others 

 from the homes given them by Nature, where they were 

 doing little harm, to new homes where they have become 

 terrible plagues. 



The kiUing of large numbers of hawks and owls, all the 

 species of which many people have wrongfully thought to 

 be harmful, has been followed by a great increase in the 

 numbers of rats and mice. We have killed off most of the 

 coyotes, the chief food of which was rabbits and ground 

 squirrels. The two latter animals have now become a 

 serious pest. They do enormous damage to the crops, and 

 we spend thousands of dollars fighting them. 



The common rabbit has in most parts of its native coun- 

 try so many enemies which are always on the lookout for 

 a good meal, that it cannot increase enough to do much 

 harm. Years ago a number of rabbits were taken to Aus- 

 traha, where there were none. Here they found a favorable 

 climate and few enemies. They have now increased so 

 that they overrun much of the continent and are a terrible 

 pest which the farmers are unable to control. 



Some years ago the gypsy moth and the browntail moth 

 were introduced by accident into the New England states. 

 Finding there a congenial climate and few enemies, they 

 increased rapidly. They soon began to strip the leaves 

 from the beautifuj elms which make the streets and parks 

 of this region so attractive. Now these moths have turned 

 their attention to the white pine and are doing an ever-in- 

 creasing amount of damage ; and although they are being 



