5^Q Life-histories of Northern Animals 



long by A to ^ inches thick. The pile itself was 7 inches 

 by 5 wide and 3 high, and contained by computation 10,000 

 pellets. Several thousand times that winter, then, had these 

 exemplary little beasts put themselves to the inconvenience 

 of stepping out of the back door, to avoid soiling their nests. 

 It was at a place where two back doors or minor tunnels 

 opened out (see Fig. 151). This habit of voiding dung at a 

 certain place is a beginning of civilization. Three specimens 

 from this colony were identified by Dr. Merriam as M. drum- 

 moftdi. 

 NESTS M. pennsylv aniens (that used to be Arvicola riparius) is 



the eastern form of drummondi and the same in its way of life. 

 Merriam writes thus of its habits in the Adirondacks:^^ 



** In early spring its nests are generally made just beneath 

 the surface, but, after the grass has attained a little height, 

 they are usually placed in slight depressions directly on the 

 ground." This agrees with my own observation on the 

 present species. 



It has the habit, also, of making a number of winter nests 

 under the snow. These are usually of chewed grass and 

 straw, very warm and cosy. In these it nurses the young. 



MATING Its mating habits are quite unknown. It may be promis- 



cuous. 



YOUNG To breed like Rabbits is an old measure of fecundity, but 



those who established the standard were not fully acquainted 

 with the Microtinae. These Mice can marry, multiply, and 

 raise to independent age a whole family before the Rabbits get 

 much beyond the period of gestation. They begin in the early 

 spring, or even late winter, and seldom stop before snowfall; 

 meanwhile, the young of the first broods are at work assisting 

 in the noble work of multiplying the race, supplying fresh 

 toilers for the task of converting a world of vegetable matter 

 into a world of sublimated flesh and blood, for the service and 

 sustenance of the vast tribes of mouse-parasites known as 

 birds and beasts of prey. 



" Mam. Adir., 1884, p. 275. 



