30 . AN ECONOMIC STUDY OF FIELD MICE. 



The following winter. 19CM:-5, mice and rabbits were again abun- 

 dant in the orchard, having come in from adjacent territory. The 

 experiences of the preceding winter were repeated, except that cover 

 for mice was less dense and the campaign against them began much 

 earlier in the season. 



During the two winters named, many other orchards throughout 

 eastern Kansas were seriously injured by field mice. As a rule no 

 preventive measures were used, and the total losses were enormous. 



THE RELATION OF FIELD MICE TO THE FARMER. 



In 1886 the Biological Survey sent out a circular letter of inquiry 

 about damages to crops by mammals. A great many replies from 

 widely scattered places were received. The replies relating to field 

 mice show that these animals everywhere are regarded as a pest. 



The following extracts from letters on file in the office of the 

 Bureau of Biological Survey are here presented to show not only 

 how great is the amount of injury from field mice in certain localities, 

 but to give an idea of the wide area over which losses are sustained. 



REPORTS EROM FARMERS AXD OTHERS. 



Field, mice are very injurious to clover fields. The injury is done by eating 

 the roots when the ground is covered with snow. The loss is serious. They are 

 injurious to fruit trees and yellow locust and Osage orange. They girdle them 

 beneath the surface of the ground during deep snows. They destroy apple and 

 pear trees, but rarely hurt peach and cherry. 



—Gap, Lancaster County, Pa., Nov., 1886. 



Field mice injure pastures and meadows by burrowing under grass roots and 

 destroying them. There were more last summer than for years, I think, owing 

 to the destruction of their natural enemies. 



— Eastbrook, Lawrence County, Pa., Feb., 1887. 



Meadow mice are very destructive to grain, grapes, and trees. This fall 

 (November, 1886) three or four years ago. the fields were swarming with them. 

 I went out with my little boy and we killed 56 in an orchard in less than two 

 hours. In going half a mile from the station the dog picked up 15. They 

 ruined several hundred fine apple trees for me. some of them several inches in 

 diameter. Many thousand trees were ruined in this country. They prefer 

 apple to plum or peach bark. — Huron, Mich.. Nov., 1886. 



This has been a periodical year for their invasions and the damage has been 

 great in many fields and meadows, particularly potato fields, which have been 

 badly damaged where the surface was grassy. They injure to a slight extent 

 cabbage buried in the ground. Clover fields and wheat have also been damaged. 

 They do great injury to cornfields, eating the grain and even climbing up the 

 stalk to the ears. All kinds of vegetables are eaten. Pastures are devastated 

 for rods where the grass is high enough to hide the mice. Other invasions 

 occurred in 1883 and 1888. Fruit trees are not injured except in cases where 

 there is straw or other litter : then the trees are girdled by gnawing. 



—Camp Point. Adams County. 111., Nov., 1889. 



a Circular No. 3, On the Economic Relations of Mammals. 1886. 



