78 USEFUL BIRDS. 



ment made by Childrey as to the assemblage of Owls when 

 the field mice swarmed in Essex in 1580 received confirma- 

 tion during 1892. Local observers reported that, after the 

 great increase of voles was noticed, the Short-eared Owl 

 (^Asio flamnieas) became much more numerous on the hill 

 farms, and that many pairs, contrary to precedent, remained 

 to breed. 



Dr. W. B. Wall expresses the opinion, from his experience 

 with the pests, that their chief enemies are the Owl and the 

 Kestrel (a Hawk), which do more to reduce their ranks than 

 all the traps of the farmers and the "microbes of the scien- 

 tists" combined. Both farmers and game keepers in England 

 and Scotland are inclined to regard these birds as vermin, to 

 be shot at sight. 



In some parts of the United States the destruction of the 

 natural enemies of rodents by man has been so complete that 

 these animals have greatly increased in numbers. Prairie 

 hares, or Jack rabbits, as they are called, became so numer- 

 ous in some States at times that they could not be kept in 

 check by ordinary hunting, and the people of whole town- 

 ships congregated to drive them into great pens, where 

 thousands were killed with clubs. Gophers or spermophiles 

 have so increased in numbers that they have become pests. 

 Farmers have been obliged to resort to extraordinary meas- 

 ures to destroy them. In Montana such large sums were 

 paid out in six months of 1887 in bounties for the destruc- 

 tion of ground squirrels or gophers and prairie dogs, that 

 a special session of the Legislature was called to repeal the 

 law, lest it should bankrupt the State. 



In New England our common hares (miscalled rabbits) 

 are kept in check in thickly settled regions by hunters; but 

 the field mice, which are not subject to this check, have 

 increased so rapidly in many localities that diu-ing the hard 

 winters of 1903-04 and 1904-05 thousands of young fruit 

 trees in the New England States were attacked by them and 

 ruined. These mice have become so numerous that in some 

 places young trees cannot be grown unless protected from 

 them. They also destroy a great quantity of grass and grain, 

 some small fruit, and vegetables. Unfortunately, the food 

 habits of these little animals have never been fully studied. 



