Vo 1. 6, No. 2 
Page 3 
the number of young entering the fall population and weather during the breeding sea¬ 
son. However, the numerical increase in rabbit numbers from spring to fall was ap¬ 
parently related to the amount of precipitation during the previous winter. The more 
rain and snow falling from December through March the fewer rabbits produced during 
the following breeding season. A possible explanation for this lies in the stress 
concept of Selye. According to this concept, previously stressed animals cannot with¬ 
stand additional stresses. It is postulated that does entering the breeding season 
in poor physical condition as a result of stresses occuring during severe winter 
weather cannot withstand additional stresses imposed by successive litters. This hy¬ 
pothesis needs testing before data on winter weather can be used to predict trends in 
the fa 11 popu1 at ion. 
Table I. Fluctuations in the abundance of cottontails on the 4-H study area at 
Allerton Park, 1956-1962. 
Year 
1956 
1957 
1958 
1959 
I960 
1961 
1962 
Spring pODulation 
mm mm 
47 
31 
132 
56 
161 
24 
Fal1 population 
333 
259 
324 
239 
309 
363 
107 
Harvest 
113 
92 
109 
95 
0 
167 
0 
Decrease from fall to spring 
-- 
686 
228 
192 
183 
148 
339 
Decrease due to hunting 
-- 
113 
92 
109 
95 
0 
167 
Decrease due to other factors 
— 
173 
136 
83 
88 
148 
172 
Percent loss of the fall population 
— 
86 
88 
59 
77 
48 
93 
Percent loss to hunting 
• •» 
40 
40 
57 
52 
0 
49 
Percent loss to other factors 
-- 
52 
53 
26 
57 
48 
48 
Increase from spring to fall 
— 
212 
293 
107 
253 
202 
83 
Percent increase from spring to fall 
mm mm 
451 
945 
81 
452 
125 
346 
5. R esponses o_f Bobwh i tes and Pra i r ie Ch i ckens to Hab i tat Manipulation 
J. A. El 1 Is, R. J. Ellis 
A census of prairie chickens in Jasper County during early February revealed 
three flocks which contained an estimated 141 birds. One of these flocks, located 
near Bogota, contained approximately 125 birds; the other flocks were found near 
Wakefield and West Liberty. A similar census of prairie chickens in Crawford County 
revealed a single flock of about 10 birds; the flock was located near Annapolis. 
These censuses were made by interviewing three farmers in each area of the county from 
which prairie chickens had been reported during the fall of 1962 by vocational agricul¬ 
tural students. 
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