Vol. 25, No. 9 
Page 2 
The winter of 1981-02 was one of the most severe on record in Illinois. 
However, the effects of severe weather during the cold season of 1981-82 appear 
to be more localized than those of the statewide winter storms in 1976-77 and 
1977-78 that decimated pheasant populations. The Illinois Cooperative Crop 
Reporting Service reported near-normal temperature and precipitation for counties 
in the West Crop-Reporting District during the 1981-82 cold season. However, 
weather data for the West, Central, and East crop-reporting districts indicate 
that winter temperature and precipitation patterns became more severe from west 
to east. Hence, winter weather patterns during 1981-82 appear to correspond with 
the relative declines noted for pheasants in central Illinois (Table 1). 
Ecology and Management of Squirrels - W-66-R C.M. Nixon, 
L.P. Hansen 
If adult fox squirrels are intolerant of other fox squirrels, especially 
those of the opposite sex, we would expect higher immigration rates where adults 
have been removed than where adult densities are intact. As described in a 
previous newsletter (MWRL 25(8):2), we manipulated adult densities on 5 study 
plots and maintained 1 control plot. Although adult removals were generally 
successful, in a few instances adult densities recovered to near normal levels 
before a subsequent removal. To reduce any bias resulting from these instances, 
we classified adult fox squirrels in 2 density classes—high, > 0 . 50 /ha and low, 
<0.50/ha--and calculated recruitment for each density class (Table 2). 
Table 2. Recruitment (number of unmarked fox squirrels/ha) on grids with high 
and low densities of adult males and females. 
Recruitment 
Adult 
Year 1 
ing 
Juvenile- 
Subadult 
Total 
Ma 1 e 
Female 
Male 
Female 
Male 
Female 
Male 
Female 
Fall 
Males 
High Density 
0.22 
0.42 
0.09 
0.10 
0.68 
0.84 
0.93 
1.54 
Low Density 
0.33 
0.18 
0.31 
0.19 
0.41 
0.07 
1 .05 
0.64 
Females 
High Density 
0.29 
0.22 
0.28 
0.14 
0.35 
0.30 
0.92 
0.68 
Low Density 
0.23 
0.46 
0.03 
0.15 
1 .03 
1.12 
1.29 
1.71 
Spring 
Males 
High Density 
0.09 
0.19 
0.35 
0.10 
0.17 
0.17 
0.60 
0.46 
Low Density 
0.18 
0.20 
0.21 
0.13 
0.16 
0.14 
0.55 
0.46 
Females 
High Density 
0.18 
0.14 
0.14 
0.03 
0.13 
0.03 
0.46 
0.23 
Low Density 
0.12 
0.23 
0.35 
0.20 
0.20 
0.24 
0.67 
0.67 
