1908] 
Jacl-soii, List of Wifico)isin Mammals. 
19 
I have observed them out of their burrows in the autumn was 
November i, 1903, at Milton. 
Marmota monax (Linnseiis). 
Woodchuck ; Ground Hog. 
Marmota monax probably occurs over the whole of Wisconsin 
in favorable localities ; it is most abundant in the southern counties 
and appears to be quite common as far north as Barron and Lang- 
lade Counties. It undoubtedly will be found less abundantly 
northward to Lake Superior, but we have seen no specimens from 
that region. 
Sciuroptems sabrinus (Shaw). 
Northern Flying- Squirrel. 
The large northern flying squirrel is found in the extreme 
northern counties of the State. It is probably not uncommon in 
favorable localities but it is seldom observed on account of its 
nocturnal habits. Specimens have been examined from Iron and 
Price Counties. 
Scriuropterus volans (Linnaeus). 
Flying Squirrel. 
The southern form of Sciuropterus is found wherever there is 
suitable hardwood timber in the state. During the day it remains 
concealed in a nest composed of grass, moss, plant down and fur, 
which is generally situated in a small cavity in an oak or poplar ; 
cavities made by woodpeckers are preferred but sometimes natural 
cavities are chosen. Flying squirrels are nocturnal in habits and 
are seldom observed ; however, a few sharp raps with a stick upon 
the trunk of the tree will usually bring them from their nest cav- 
ities if they are at home. 
Castor canadensis Kuhl. 
American Beaver. 
Beavers at one time were not uncommon along many of the 
streams in northern Wisconsin ; remnants of beaver dams and 
