MONTHLY WILDLIFE RESEARCH LETTER 
AP R 
Illinois Federal Aid Projects W-66-R and W-87-R 
Department of Conservation and Natural History Survey, Cooperating 
Glen C. Sanderson and Eva Steger, Editors 
Urbana, Illinois 
March, 1980 
Vol. 23, No. 3 
Manipulation of Pheasant Habitat - W-66-R £• Warner 
Winter-sex-ratio counts of pheasants are conducted in January-February on 
study areas in the east-central counties. It is assumed that the ratio of cocks 
to hens after hunting provides a crude index of the proportion of cocks taken by 
hunters. 
Sex ratios in east-central Illinois during the i 960 's averaged approximately 
25 cocks per 100 hens; 30.5 cocks per 100 hens were counted following the 1976-77 
hunting season (Table 1). The high ratio of cocks to hens from 1978 to 1980, the 
highest in recent decades (Table 1), reflects effects of severe winter weather 
and subsequent changes in hunting pressure. 
Severe vj’c^ter storms decimated pheasant populations in east-central Illinois 
in late January 1977 and again during the winter of 1977-78. Hunters responded 
to the scarcity of ringnecks with fewer and shorter hunting attempts In the field. 
The percentage of cocks harvested in east-central Illinois has traditionally 
been related to pheasant densities; winter sex ratios for recent years (Table 1) 
reflects this phenomenon. 
Table 1. 
Illinois, 
Winter Sex Ratios (January- 
1977- 1930. 1 
■February) of Pheasants 
in East-central 
Pheasants 
Cocks per 
Percent 
Year 
Counted 
100 Hens 
Cocks 
1977 
848 
30.5 
23.3 
1978 
597 
45.6 
31.3 
1979 
412 
61.6 
38.1 
1980 
249 
59.6 
37.3 
Counts were made primarily on study areas in Champaign, Ford, Iroquois, 
and McLean counties; personnel from the Department of Conservation assisted In 
sex ratio counts. 
