140 Bulletin Wisconsin Natural History Society [Vol. 13, No. 3 
Of the birds, such species as the prairie chicken, the prairie 
horned-lark, bobolink, meadowlark, vesper and grasshopper 
sparrows may be said to be representative. 
Between the woods and the open fields, we find again a well 
defined seasonal succession, and the meadow vole and the deer 
mouse are the migrants. Winter finds these species both 
in the shelter of the woods, though there is a considerable 
amount of shelter to be had even in the tall grass and in the 
Fig. 6. The Edge of the Woods. 
island-like clumps of hazel brush ( Corylus americana). The 
deer mouse is relatively inactive during the winter, while the 
vole is to be found running about among the fallen leaves in 
the shelter of the branches of a fallen tree or clump of bushes, 
and sometimes traveling out into the open fields in its tunnels 
through the snow. The entrances to these tunnels are often 
the most striking feature of open places in the woods, while the 
tracks of the animal at times are very numerous. With the 
