Vol. h, No. k 
Page 2 
Table l e —Average age of cottontail rabbits from hunters 1 samples. 
Region 
1959-1960 
1960-1961 
Total 
Average 
Age (months) Number 
Average 
Age (months) Number 
Average 
Age (months) 
Nxxmber 
South 
9.97 
322 
8.50 
1,161 
8.82 
✓ 
1,U83 
Prairie 
8.57 
198 
7.05 
109 
8.03 
307 
West and 
Northwest 
8.63 
389 
7.90 
196 
8.39 
585 
TOTAL 
9« 09 
909 
8.31 
1 ,U 66 
8.61 
2,375 
It is apparent that rabbits live longest in the southern part of the state, 
while the shortest survival rate is experienced in the prairie counties. Also,, 
it appears that there was a general decrease in the average age of rabbits in 
all three regions from the first to the second year. This decrease in average 
age was caused by an increase’ in the mortality rate betx^een the first anu the 
second year. This means that,at least last year, the rabbit population was on 
the downhill side of the population cycle. With several additional years of data, 
prediction of state-x-ri.de popxilation levels should be possible. 
An interesting fact noted this year'was that although the total number of 
eyes received was greater than last year, the nxxmber of eyes received from 
cooperating hunters decreased markedly. Only the action of several conservation 
officers saved the program and their action pointed the way to the futxire success 
of this project. In the future all conservation officers in the state will be 
furnished xri.th a rugged container for collecting rabbit eyes during the season. 
The container will be filled xri.th the preservative. 
W-55-R-5 F. C. Bellrose 
Three aerial sxirveys of waterfowl populations in the Illinois, Mississippi, 
and Rock River valleys were made dxxring April. As a result of inclement flying 
weather, censuses were made at intervals slightly greater than one x^eek: April 
7 , 18, and 26. 
