MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
T, G. Scott, Editor 
Urbana, Illinois 
December 1958 
Vol. I, No. 12 
W-30-R-12 R. F. Labisky 
A preliminary estimate indicated that only 37.8 per cent of the cocks 
were eliminated from the population on the Sibley area by hunters during the 
1958 hunting season. The estimate was based on the change between the preseason 
sex ratio of 80.7 per cent cocks, obtained from the night-light trapping of 358 
pheasants, and the postseason ratio of 25.3 per cent cocks, obtained from road¬ 
side counts of 1,183 birds during December. In contrast, 73.3 and 20.3 per cent 
of the cocks were harvested during the 1956 and 1957 hunting seasons, respectively. 
A total of 595 hunters were interviewed, and I 1 I 48 bagged pheasants were 
examined on the Sibley area during the 1958 hunting season. The age ratio among 
bagged cocks was 6.8 juveniles per adult cock. Comparable age ratios for the 
1956 and 1957 hunting seasons were 12.5 and 8.6 juveniles per adult cock, 
respectively. The hunters spent an average of 2.5 hours afield to bag each cock 
in 1958, compared to 2.3 hours in 1956 and 3.5 hours in 1957. Hunters crippled 
and lost 23.0 per cent of the number of cocks bagged in 1958 , in contrast to 
crippling losses of 38.0 per cent in 1956, and 28.8 per cent in 1957. 
W-82-R-8 R. D. Lord 
Reports of a decline in the rabbit population in the northern part of 
the state and in some parts of southern Wisconsin have been received from many 
sources. The number of rabbits seen in the spotlight census in the Sibley area 
dropped to 0.5 rabbits per mile from more than 2 rabbits per mile in November. 
Last year the spotlight census revealed 1.7 rabbits per mile in December. 
Reports have been coming in describing sick rabbits exhibiting the 
same symptoms (carrying the head to one side, running in circles, stumbling, 
ascending paralysis) that are typical of a new disease discovered by members of 
this project. Preparation of a manuscript describing this new disease has been 
started. 
OCT 9 1959 
NATURAL 
HISTORY SURVEY 
LIBRARY 
