82 RODENTS OP IOWA 



vegetation and of the roots and seeds of grain and grasses. In win- 

 ter grain and various kinds of roots are substituted for the leaves- 

 and stems. If green vegetation is lacking, young apple orchards, 

 forest trees, or shrubbery are often attacked if they are convenient 

 and considerable damage is done. Such depredations occur most 

 often in winter, though they are not confined to this season, for 

 summer girdling of trees has been noted in many instances. 



"Stomach examinations show that in addition to bark, green 

 leaves, and seeds of grasses and sedges, field mice eat all kinds- 

 of bulbs, tubers, and roots and occasionally animal food. The 

 larger aquatic species are said to eat mollusks, and crayfish. When 

 a number of these mice are kept in confinement, the stronger 

 animals usually devour the weaker, and our field naturalists have 

 frequently noted that trapped field mice are devoured by their 

 brethren 



"It has been calculated that each adult meadow mouse requires 

 from 24 to 36 pounds of green vegetation per year. It is thus ap- 

 parent that the total amount eaten by the hordes that ordinarily 

 infest the meadows, swamps and forests of our country is incal- 

 culable, and is a steady drain upon the resources of the farmer."" 

 (Lantz, I. c. 368). 



In addition to the kinds of food mentioned, the meadow mouse 

 feeds to a considerable degree upon roots of wild morning-glory,, 

 cat-tails, and sweet clover. 



Numerous complaints have come in from various parts of the 

 state concerning depredations upon trees, pastures, and gardens by 

 meadow mice. Damage is often more widespread than is ordinarily 

 believed, since injury actually caused by the meadow mice is often 

 attributed to rabbits and gophers. Damage done by meadow mice 

 can usually be recognized by the small, narrow tooth-marks and by 

 the fact that it is lower down on the trees than that ordinarily done 

 by rabbits. In consideration of the great prolificacy of the species 

 and the large amount of food required by a single individual during 

 a year it is evident that where local conditions have been favorable 

 to an undue increase of the animals considerable loss to agricul- 

 tural interests is sure to follow. Where meadow mice are present 

 even in normal numbers) the loss though not serious may be worthy 

 of consideration in these times of conservation. 



The meadow mouse works under the snow in winter, burro wing- 

 along the roots of clover, timothy, and other plants, often destroying- 



