74 RODENTS OF IOWA 



Habit's, Distribution, Etc. — The prairie white-footed mouse seems 

 to be confined to the open prairie and cultivated fields of the Mis- 

 sissippi Valley. In Iowa it is distributed practically throughout 

 the state and seems to be at least no less common than the northern 

 white-footed mouse. 



This mouse inliabits dry cultivated fields and prairies, and, to 

 some extent, is found in small sparsely wooded areas. Ruthven and 

 Wood report that the nine specimens secured in Clay and Palo Alto 

 counties "were found in burrows in stubble fields, pastures and on 

 the shores of lakes. "^^ Robert Keimicott, who many years ago 

 made extensive observations on this animal, reports as follows con- 

 cerning its habits : ' ' Not having on the prairies, the shelter found 

 by its timber-loving cousins in old tree stumps and trees this species 

 digs burrows. These are rather simple, with few or no side-pas- 

 sages, and often with but one entrance, the depth and extent being 

 variable, but never great. The nest is small, composed of soft grass, 

 etc., it is spherical, and the small internal cavity is entered through 

 a narrow opening on one side. In cultivated fields the burrows are 

 frequently dug at the roots of fruit trees, the bark of which is often 

 gnawed, sometimes causing great injury. In nurseries, fruit-trees 

 are often taken up and ' heeled in ' ; that is, laid down close together, 

 with the roots placed in a trench, and then covered in such manner 

 that they are kept safely in a very small space, and can be readily 

 pulled out when desired. The loose earth among the roots of these 

 offers an inviting habitation to the mice ; and, in nurseries infested 

 by them, they will be found burrowing in almost every lot of trees 

 thus buried, where they feed upon the bark of the roots, and tlius 

 cause serious damage. In the fall, they are often found in corn- 

 shocks, making a nest among the stalks, though they do not so often 

 burrow under these as the arvieolae. But, during winter, they may 

 be tracked in corn-fields from their burrows to the neighboring corn- 

 shocks, which they have visited for food. In spring, the young are 

 always produced in burrows. During the summer, however, they 

 occasionally are observed in nests, under bits of wood or bunches 

 of hay, on the surface of the ground. In autumn, I have found 

 nests of the young in small Inirrows only a few inches below the 

 surface, or under an inverted sod. I liave never observe 1 more 

 fbnn one pair of adults occupying the same burrow, and, unlike 



i^Ruthven. A G. and Wood, N. A., Proc. la. Acad. Sci. XIX, 20-1, 3912. 



