VoI. 22, No. 6 
Page 2 
Anchor 
19-9 
5.7 
4.2 
2.5 
Harwood 
11.8 
7.1 
6.1 
5.5 
Prairie Green 
28.4 
9.2 
3.0 
8.0 
Due to unusually poor counting conditions. 
the 3 highest counts per stop 
were used in computing the average number of cock calls per area. 
Ecology and Management of Squirrels C. M. Nixon, 
L. P. Hansen 
Use of leaf nests to estimate squirrel numbers .—An essential part of sound 
management in any game species includes a knowledge of how populations fluctuate 
from year to year. Unfortunately, many state wildlife agencies cannot devote 
the large amount of time and effort necessary to obtain such data. A quick, 
simple way to estimate animal numbers would be ideal, and wildlife biologists 
have attempted to derive several indices of squirrel abundance. Counts of leaf 
nests would seem to be the most practical means of determining annual changes 
in squirrel numbers since nests are built every year and are easily countable, 
and, hypothetically, the number of nests built is directly proportional to the 
number of animals present. 
As reported in previous newsletters, leaf nests were counted for 7 years 
during the fall and 4 years during the spring on 2 study plots in east-central 
Illinois. Trapping took place concurrently with leaf nest counts so we have a 
true estimate of the number of squirrels present. Linear regression analyses 
were run to determine if there was any relationship between the number of animals 
captured and the number of leaf nests during both spring and fall. No signifi¬ 
cant relationship was found in any test and the highest r value obtained was 
only 0.26. For unknown reasons, either individual squirrels build different 
numbers of leaf nests each year, or annual fluctuation in sex ratios and age 
structure lead to changes in the number of leaf nests built. Regardless of the 
cause, the number of leaf nests should not be used to estimate squirrel numbers. 
Responses of Prairie Chickens to Habitat Manipulation R. L. Westemeier, 
D. R. Vance 
The 8,300 acres acquired by Central Illinois Public Service Company (CIPS) 
in Jasper County offer potential for management of grassland for prairie chickens 
and other wildlife. The Department of C onse rvation (DOC) and CIPS entered into 
a 25-year lease agreement on 14 March 1 979 under which DOC will manage portions 
of the Newton Power Station for conservation and public recreation purposes. 
A tract of approximately 260 acres is included in the CIPS-DOC agreement 
for management of prairie chickens and other grassland wildlife. The tract is 
located about 0.8 mile from the nearest (Otis-Fuson) prairie chicken sanctuary. 
Emphasis will be on attracting prairie chickens from the Bogota flock to the 
