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part of at least twenty-five States, from Maine to the Dakotas and 

 southward almost to 35 degrees nortli latitude. 



"While the food habits of the various species of short-tailed field 

 mice are remarkably similar, their breeding and general habits differ 

 greatly. The variety of habitats is most striking. Some species 

 prefer high ground, while others live in low, moist places. Occasion- 

 ally the same species inhabits both sorts of localities. Some species 

 live in forests, others in the open prairies. Some burrow under the 

 ground like moles, while others make smooth paths or trails upon 

 its surface. 



"Except in cold weather, nearly all species can temporarily adapt 

 themselves to moist surroundings; but a few seem to be almost as 

 aquatic as the nearly-allied muskrat. 



"The nests of field mice are compact bunches or globes, composed 

 of grass blades and other dry vegetable fibers. They are placed in 

 depressions in the ground, in shallow burrows, or supported on grass 

 stems above the ground. In brush piles the writer has found them 

 nearly a foot above the ground. Sometimes they are placed under flat 

 stones or logs or under shocks of grain. The structures are so 

 slight that a day's sunshine will dry them out after a storm, and yet 

 they are so compact that the animals pass the coldest weather snugly 

 housed in them under the snow. Trails, often of great length and 

 worn smooth by constant use, lead to neighboring feeding grounds. 



"While most surface nests are for shelter only, sometimes the 

 young, especially of swamp species, are produced in them. However, 

 the young of most kinds are born in underground nests and are 

 rarely seen unless uncovered by accident. They are at first hairless 

 and blind. 



"The common meadow mouse of the United States is one of the 

 most prolific of our species. Estimating the normal increase at six 

 young, with four litters in a season, and assuming that there were no 

 checks upon the increase, the results are appalling. A single pair and 

 their progeny in five seasons would amount to nearly 1,000.000 indi- 

 viduals. This calculation is under mark, since it is based on the 

 assumption that the young do not breed until about a year old. The 

 animals, however, mature very rapidly, and the spring young un- 

 doubtedly breed in the fall of the same year. 



"In summer the principal food of these mice is green vegetation 

 and unripe seeds of grain and grasses. As the season advances, ripe 

 grain and seeds take the place of the immature; and in winter 

 bulbous and other roots are in part substituted for stems and leaves. 

 When convenient, and green vegetation is lacking, the bark of trees 

 and shrubs becomes a staple food. It is mainly in winter that the 

 apple orchards and young forest trees suffer from attacks of mice. 



