On the basis of data obtained from trapping and from the drive censuses, 
population estimates were computed for the two areas, using the familiar 
Petersen-Linco1n index method: 
N 
n 
nr* 
thus 
m 
with the standard error of the estimate determined by: 
SE 
1 
H^n(n-m) 
where 
N = 
the 
population size 
M = 
the 
number of marked 
animals 
i n the 
popu1 at ion 
n = 
the 
observed sample 
m = 
the 
number of marked 
animals 
i n the 
sample. 
Thus, with 95 percent confidence, the estimated numbers of rabbits at 
Allerton in early November, 1963, were 132 + 22 for the 4-H Area and 80 + 17 
for the Sanctuary Area. 
When data on rabbit abundance at Allerton this year are compared with 
findings from previous years (Table 1) it is apparent that rabbit numbers are 
very little different from what they were a year ago. The lack of major chang 
in rabbit abundance from 1$62 to 1963 is particularly interesting when it is 
noted that the Sanctuary Area had been hunted in 1962 and the 4-H Area had not 
Table 1. Summary of cottontail populations and harvest on study areas at 
Allerton Park, 1956 - 1963, as determined by color-marking and drive censuses. 
1956 
1957 
1958 
1959 
I960 
1961 
1962 
1963 
Sanctuary Area 
Sp ring 
60 
42 
64 
54 
128 
54 
Fall 
238 
120 
171 
125 
141 
71 
80 
Harvest 
A 
* 
42 
/V 
35 
4-H Area 
Spring 
47 
31 
132 
56 
161 
24 
61 
Fa 11 
333 
259 
324 
239 
309 
363 
107 
132 
Harvest 
113 
92 
109 
95 
* 
167 
•A. 
/V 
* 
* Study area not subject to hunting. 
+ Hunting in progress, 1963-64 season. 
