Vol. 23, No. 11 
Page 2 
9 
Man-hours expended 
per cock observed 
SSA 
FCMU 
N.A. 
N.A. 
N.A. 
N.A. 
N.A. 
N.A. 
6.5 
2.0 
N.A. 
N.A. 
N.A. 
M.A. 
N.A. 
N.A. 
4.2 
1.6 
1 Statistics for both study areas combined. 
Ecolo gy and Management of Squirrels - W-66-R 
C. M. N i xon , 
L. P. Hansen 
Virtually all of Illinois' forests have been disturbed, often many times. 
Indiscriminate timber cutting, fires, and grazing have created a mosaic of 
stands usually less than 60 years old, with varying capacities to support 
huntable populations of squirrels. With disturbance as the normal condition in 
Illinois' forests, we must seek methods to mitigate such injurious effects as 
reduction in food production, and to promote those effects of disturbance that 
should benefit squirrels, such as diversity of tree species and age classes. 
Presently, no forests in Illinois, or indeed in the Midwest, are being 
managed for squirrels. Optimum habitat for squirrels occurs near the climax of 
a successwsnal sere. Thus, production of squirrel habitat requires either time 
for natural succession to produce the necessary life supporting elements 
(usually 30 years for succession to produce a cavity- and seed-producing stand 
in the Midwest) or money to provide artificial shelter or supplemental foods in 
a young forest. 
Most techniques recommended for managing forest habitats for squirrels are 
too general to be of much value in managing the typical Illinois timber stand. 
Such cliches as "good timber management is good wildlife management" will no 
longer suffice. Wildlife ecologists must develop models to predict consequences, 
good or bad, of timber management and other land uses on wildlife. Sufficient 
information is now available to begin this process for gray and fox squirrels. 
In the coming months we will discuss various aspects of forest management 
to benefit squirrels in Illinois. Topics to be discussed include the following: 
1. Squirrel habitat preferences in Illinois. 
2. Squirrel densities and harvest by hunters. 
3. Fall sex and age ratios and what they mean to the squirrel hunter. 
1*. Effects of clearcutting and selection logging on squirrels. 
5. Managing the forest to increase oaks and hickories. 
6 . Methods for increasing tree seed crops. 
7. Effects of nest boxes on gray and fox squirrels. 
3. Methods of increasing natural shelter for squirrels, including tree 
cavities and the climbing vines used to anchor leaf nests. 
