Vol. 14, No. 4 
Page 3 
plot of capture frequencies converted to logarithms. The maximum likelihood 
estimation for a geometric distribution of capture frequencies was 67 
squirrels. Expected capture frequencies calculated for both methods did not 
differ significantly (P > 0.05) from the observed captures. A total of 41 
individual squirrels were actually captured on this area between early 
January and mid-March 1971* 
Because of a large number of denning sites and an abundant annual seed 
crop, the mature forests of Allerton Park are high-quality squirrel habitat. 
The late-winter density of about one fox squirrel per acre, found at 
Allerton, is probably high for this species and may only occur in such 
old-growth forests. Certainly, the forests of Allerton Park provide a much 
more productive habitat for squirrels than most of the remaining forests of 
east-central Illinois. 
4. Responses of Bobwhites to Habitat Manipulation J. A. Ellis, 
D. R. Vance 
Analysis of 1,634 bobwhites harvested on the Dale Area and of 2,047 
harvested quail frcm the Forbes Area provided some insight into the sex and 
age ratios during the fall and early winter for the years 1964-70. As 
expected, the sex ratio among the juveniles on both areas was 50:50. This 
ratio among the juveniles changed appreciably as the birds became adults. 
On Dale, the mean sex ratio among adults was 63 percent males. On Forbes, 
the mean sex ratio for the adults was 57 percent males. The differential 
sex ratios among the adults were attributed to the loss of hens during 
reproductive efforts, nesting and brooding. 
The long-term mean age ratios were 17 percent adults on Forbes and 15 
percent adults on Dale. These data agree generally with the turn-over rates 
of 80-85 percent, for quail populations, reported in the literature. 
5. Response of Pra i r i e Ch ickens to Hab ? tat Manipulation R. L. l/estemeier 
As in the past eight springs, booming ground surveys were conducted 
this spring on the Bogota Study Area at no less than weekly intervals from 
mid-March through mid-April. These data were supplemented by observations 
recorded by visitors in blinds on booming grounds. Counts were made during 
the first hour after daybreak, and an effort was made to determine the 
maximum number of cocks on the area. 
The peak count of 159 cocks at Bogota this spring was 47 percent higher 
than the peak count in the spring of 1970* This is the third consecutive 
increase in the Bogota flock. The count this spring is 104 percent higher 
than the count made in 1963 , when this census was initiated, and 330 percent 
higher than the lew year of I 968 . 
Except for three minor booming grounds involving only two or three cocks 
each, all booming was located on or within 200 yards of the sanctuaries. 
Between 1970 and 1971, the counts roughly tripled on the Otis, Field, and 
