Vol. 15, No. 7 
Page 2 
Ecology and Management of Sgui rre 1 s C. M. Nixon, 
R. E. Greenberg 
During the 14 sguirrel-hunting seasons from 1956 through 1969, which 
we shall use as our long-term base, the number of squirrels bagged by Illinois 
hunters averaged 2.83 million per year. A high of 3.64 million squirrels 
in the bag was recorded in 1957, and a low of 2.37 million occurred in 1 965 
(Illinois Dept. Conserv. Tech. Bull. 4, 1971). 
The Southern Conservation Zone, here defined as the 51 southernmost 
counties in the state, accounted for a mean kill of 1.68 million squirrels 
per year (59-3 percent of the statewide harvest) during the base period of 
1956-69. Hunting pressure in the Southern Zone was also high, despite the 
fact that 85 percent of the state's 11.1 million people reside in the Northern 
Zone (here defined as the 51 northernmost counties). Illinois squirrel hunters 
averaged 1.41 million hunter-trips per year, 1956-69, 5^.7 percent of them 
in the Southern Zone. Hunter success was notably higher in the Southern Zone 
(an average of 2.18 squirrels reported bagged per hunter-trip) than in the 
Northern (an average of only 1.80 squirrels per hunter-trip). Randolph and 
St. Clair counties ranked 1 and 2, respectively, in both squirrel harvest 
and hunting pressure during the 14-year period. 
The gray squirrel accounted for most of the difference in harvest 
between the two zones during 1956 and 1957 , when the harvest data were collected 
by species. The statewide kill of fox squirrels for the 2 years, estimated 
at 4.69 million, was nearly equally divided between the zones (49.6 percent 
in the Southern Zone, 50.4 percent in the Northern Zone). The kill of gray 
squirrels, estimated at 1.64 million, was unevenly distributed, with 79.6 
percent of the harvest occurring in the Southern Zone. 
The comparative relationship between the two Conservation Zones, in terms 
of squirrel hunting, is probably the result of differences in the amount of 
forest and abundance of squirrels—differences that modify or stimulate hunter 
interest in squirrels as game animals. 
Responses of Bobwhi tes _to Habitat Manipulation 
The mean numbers of bobwhite calls recorded per stop along standardized 
routes on the Forbes and Dale areas have been used as indices of fall popula- 
tion densities (MWRL 12(9):2) on these areas. Analysis of data for 1964-71 
showed significant regressions (P <0.005) between the numbers of bobwhite 
C ? ' S P 6 " ’ ,stemng stop and the fall population estimates obtained by censuses 
with bird dogs. Predicted population levels for fall 1972, based on these 
are . Z+K6 and 21 - 8 q^i 1 per 100 acres for Dale and Forbes, 
espectively These estimated densities for 1972 represent an 11 percent 
increase in the prehunt denisty on Dale and a 10 percent decrease in the 
prehunt density on Forbes, compared with the estimates made in 1971 . 
