1915] 
Cahn: Ecology of Wingra Springs Region 
141 
advent of the warmer weather, a majority of the voles leave 
the woods, and seek the more abundant food which the open 
fields have to offer. 
5. The Sylvan , or Woods Association. This association in- 
cludes all of the woods proper, which lie in two large areas 
separated by the small clearing through which flows the stream. 
The trees are of fair size, being eight to twelve inches in diameter, 
in the case of the older trees, and of the following species; red 
oak, white oak, aspen, hard maple, and elm. This association 
is exemplified by the presence of the DeKay snake, found 
hiding under semi-decayed logs; the skunk, of which animals 
there is but a single pair at present; the fox squirrel, arid the 
common chipmunk. On the tree-trunks, particularly on the 
white oak the tree toad is sometimes found, and this is the only 
sylvan amphibian in the formation. In as much as Hyla versi- 
color has also been taken in the swamp, it can hardly be called 
characteristically sylvan, though it undoubtedly is more com- 
mon in the woods than in the swamp. 
Sylvan birds there are in numbers. The two woodpeckers, 
downy and hairy, together with such species as the barred owl 
and the great horned owl, the partridge (during the spring and 
summer), the vireos, and flycatchers are perhaps the most 
characteristic. 
VI. THE BIRDS OF THE AREA 
In a region as diversified as the area under discussion it is 
not surprising that bird life is abundant. Wild, largely undis- 
turbed as yet by man’s handiwork, with an abundant food sup- 
ply and plenty of natural protection, the region is almost ideal 
from the point of view of the ornithologist. To the above let 
be added the relative inaccessibility of the place, and it will 
be understood that the conditions of life here are still about as 
primitive as can be found in a region as well peopled as southern 
Wisconsin. 
There is, of course, a great difference in the species as well 
as in the abundance of these species found in the different 
associations. Each association has its own typical avifauna, 
and, though these overlap, a fairly definite list of species may 
be compiled for each association. Such a list is given in Table II. 
