Vol. 7, No. 4 
Page 3 
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Because the two state wildlife areas will soon be dedicated, respectively, as 
the Sam Dale Conservation Area (Wayne County) and the Stephen A. Forbes Conservation 
Area (Marion County), they will be referred to as the Dale and Forbes areas in these 
reports. 
Censuses of the prebreeding quail populations on the study areas were made 
during the first 2 weeks of March. Fourteen coveys containing 100 quail were 
observed on the Alma Study Area. Fifteen coveys having 117 quail were located 
on the Forbes Study Area, and eight coveys comprising 46 birds were flushed on the 
Dale Study Area. The prebreeding populations on the Forbes and Dale areas had 
declined 42 and 48 percent, respectively, from the posthunt populations of 202 
and 88 birds. 
The annual census of prairie chickens on booming grounds on selected areas 
in southern Illinois was conducted during the first 2 weeks of April, 1964 (Table 
1). Three or more counts were made on each area, and the count which included the 
largest number of cocks was taken as the census figure. All counts were made dur¬ 
ing the first hour of daylight. 
Ten of the 11 areas used for the 1964 census were also used in 1963 (see 
Monthly Wildlife Research Letter, April, 1963)- The area added in 1964 surrounds 
Hunt, in Jasper County, and includes the 4-square-mile area where Dr. Ralph E. 
Yeatter censused prairie chickens each year from 1936 to 1963 (Yeatter 1963:745)- 
This area was added to provide a continuation of Dr. Yeatter's data and as an 
^ eventual replacement for the West Liberty area, where prairie chickens are nearing 
extinetion. 
Six of the areas used for the censuses of 19&3 and 1964 were increased in 
size prior to the 1964 census. In 1963, the average size of the census areas was 
9-3 square miles; during 1964, the areas contained 10-16 square miles each and 
averaged 11.9 square miles. The smaller areas were increased to obtain more 
reliable data on individual flocks. 
The census of 1963 revealed 311 prairie chickens (both sexes) on 10 areas. 
During 1964, 290 prairie chickens (254 cocks, 36 hens) were counted on 34 booming 
grounds on 11 census areas; only 251 chickens (216 cocks, 35 hens) were counted 
on the acreage used for the 1963 census. The additional chickens counted in 1964 
were observed on acreage added to the 1963 census areas. Therefore, a reduction 
of approximately 19 percent in the number of chickens on the 1963 census areas 
is indicated for 1964. 
If the indicated rate of reduction continues, and assuming there were less 
than 2,000 prairie chickens in Illinois during 1962 (see Monthly Wildlife Research 
Letter, November, 1962), only about 650 prairie chickens would remain by 1968 . 
The extinction of prairie chickens in Illinois appears a distinct possibility for 
the near future. Therefore, strenuous efforts for their preservation are imperative 
in 1964. 
Yeatter, Ralph E. 
| 1363- Population responses of prairie chickens to land-use changes in 
" Illinois. J. Wildl. Mgmt. 17(4):739-757. 
