30 AN ECONOMIC STUDY OF FIELD MICE. 
The following whiter, 1904-5, mice and rabbits were again abun- 
dant in the ore-hard, having come in from adjacent territory. The 
experiences of the preceding winter were repeated, except thai 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 FROM FARMERS AND 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 
thej-e is straw or other litter: then the trees are girdled by gnawing. 
— Camp Point, Adams County. 111.. Nov., 1889. 
"Circular No. 3, On the Economic Relations of Mammals. 1886. 
