Family CRICETIDAE 175 



weaned at 2 or 3 weeks of age. Because of their great fecun- 

 dity, meadow voles may overrun fields during favorable years 

 with as many as 100 or 200 individuals per acre. A disease epi- 

 demic or a food shortage may reduce the population within a 

 year to as small a number as 2 to 10 per acre. 



Signs. — Tracks, burrows, runways, and nests of the meadow 

 vole are like those of the prairie vole. When the meadow vole 

 walks, its footprints are paired ; the prints of the hind feet fall 

 just a little short of those of the front feet. When it runs, its 

 footprints occur in groups of four; prints of the hind feet lie 

 opposite one another and those of the front feet lie behind them, 

 generally one not so far behind as the other. This pattern of 

 footprints, and the fact that a tail mark is seldom present, may 

 help to distinguish tracks of the meadow vole from those of 

 the deer mouse. 



Occasionally, meadow vole tracks, fig. 30, may be seen on the 

 surface of snow, but usually voles keep to their maze of run- 

 ways beneath it. The abundance and complexity of these run- 

 ways show best after the snow has melted. 



Piles of grass cut about an inch long and small dark brown 

 or black droppings in surface runways are signs of the meadow 

 vole or the prairie vole. The nest of the meadow vole is de- 

 scribed in a paragraph on the life history of the animal. 



Distribution. — The meadow vole is fairly common in ex- 

 treme northern Illinois and is known to occur as far south as 

 an imaginary line drawn between Kankakee and Havana. The 

 subspecies in Illinois is Microtus pennsylvanicus pennsylvanicus 

 (Ord). The range of the species includes all of Canada except 

 the west coast ; it extends westward into Alaska and south- 

 ward in the United States as far as northern New Mexico, 

 northern Missouri, northern Illinois, eastern Kentucliy, northern 

 Georgia, and South Carolina, fig. 93. 



MICROTUS OCHROGASTER (Wagner) 



Prairie Vole Prairie Meadow Mouse 



Description. — The prairie vole, fig. 4, is a short-tailed, me- 

 dium-sized mouse that is common in Illinois fencerows, open 

 grasslands, and meadows. The upper parts are a brownish gray, 

 with a grizzled appearance resulting from a mixture of yellow- 

 ish brown and black hairs. The under parts, particularly the 



