6 FAKMEES^ BULLETIN 670. 



little from meadow mice in general food habits, their surroundings 

 afford them a larger proportion of mast. They are less proUfic than 

 meadow mice, but this is more than made up for in the fact that in 

 their underground life they are less exposed to their enemies among 



Fig. 5. — Field mouse caught in baited guillotine trap. 



birds and mammals. Like meadow mice, they sometimes become 

 abnormally abundant. 



In the eastern part of the United States pine mice do more damage 

 to orchards than do meadow mice, partly because their work is undis- 

 covered until trees begin to die. The runs of meadow mice under 

 grass or leaves are easily found and the injury they do to trees is 



Fig. 6.— Field mouse caught in unbaited guillotine trap. 



always visible. On the other hand, depredations by pine mice can be 

 found only after digging about the tree and exposing the trunk below 

 the surface. The roots of small trees are often entirely eaten off 

 by pine mice, and pine trees as well as deciduous forest trees, when 

 young, are frequently killed by these animals (fig. 4). 



