Vol. 25, No. 7 
Page 2 
One of the male-removal plots (Busch) was the only site not located in 
Allerton Park. During fall 1981 and spring 1932, reproductive rates on Busch 
were extremely low (11% and 17%, respectively), unlike those for squirrels on 
the Park plots. Adult males had been intensely cropped on Busch and few adult 
males had been recruited during these periods. While it seems unlikely, we may 
have removed so many males that females were not being bred, or some other 
phenomenon unrelated to the experiment may have caused the low reproductive 
rates. For whatever reason, the desired test of the effect of male removal on 
reproduction probably was not realized. When the results from Busch are dropped, 
fall and spring reproductive rates on the male-removal plot increase (Table 1). 
Although reproductive rates among plots were not significantly different, 
these rates were consistently higher on the experimental plots than on the 
control. It is not clear, however, which if any segment of the population most 
strongly affected density. Reproductive rates are probably determined by a 
myriad of interacting intrinsic and extrinsic factors, one of which involves in 
some way the densities of sex and age components of the population. 
In next month's newsletter we will discuss the effect of the removal on 
survival rates. 
Table 1. Reproductive rates of fox squirrels on experimental and control plots. 
Adul t 
Adul t 
A11 
No 
males 
females 
adults 
squirrels 
removed 
removed 
removed 
removed 
Allerton Allerton 
A11erton 
A1lerton 
Control 
B & Busch B alone 
A & C 
D 
plots 
Adults 
Fall 
N 
25 
16 
15 
3 
12 
H lactating 
12 
11 
7 
1 
3 
% lactating 
48 
69 
47 
33 
25 
Spring 
N 
79 
3** 
16 
8 
23 
it lactating 
50 
24 
13 
6 
15 
% lactating 
63 
71 
81 
75 
65 
Yearlings 
N 
10 
4 
9 
1 
3 
if lactating 
A 
2 
5 
0 
0 
% lactating 
1*0 
50 
56 
0 
0 
