MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
Glen C. Sanderson and Helen C. Schultz, Editors 
Urbana, 111inois 
April 1964 
Vol. 7, No. 4 
1. Pheasant Popu1 ations and Land Use J. E. Warnock 
At least 50 percent of the pheasants present on the Sibley Study Area during 
early fall, 1963; were not present by late February, 1964. About 16 percent of 
the loss from the population could be attributed directly to hunting; it was 
estimated that 9*5 percent of the hens and 37*1 percent of the cocks were shot dur¬ 
ing the 1463 season. In view of the apparent high level of nonhunting losses occur- 
ing among birds of both sexes, prevision for some type of hen harvest and a 1iber- 
alizacion of hunting regulations for pheasants should be considered. 
The above estimates of population losses are conservative, because the basic 
assumption was made that the only mortality suffered by adult hens, the age-class 
utilized to estimate losses for all other age-classes, was a result of hunting. 
A more realistic estimate of adult hen mortality would probably range between 20 
and 30 percent for the October-February period each year; thus, the estimates of 
losses for the other age-classes would be proportionally higher. 
Changes in composition of the Sibley pheasant population between October 1963 
and February 1964, were estimated from trapped birds. Sizes of samples were 1,001 
for October-November 1963; and 1 63 for February 1964. 
Age-Class 
Number per 
100 Adult Hens 
Percentage Loss 
Total 
Prehunt 
Posthunt* 
Hunting 
Unknown 
Causes 
Adult Hens 
100 
100 
9.5 
? 
9.5 
Juvenile Hens 
171 
87 
9.5 
39«6 
49.1 
Juvenile Cocks 
168 
31 
37 . 4 ** 
44.1 
81.5 
Adult Cocks 
17 
8 
34.2** 
18.7 
52.9 
All Birds 
456 
226 
20.7 
29.7 
50.4 
7 Corrected Cor a 9*5 percent illegal kill of hens; the average estimated rate of 
illegal hen kill for 1959-62 was based on fluoroscopic examination of winter trapp¬ 
ing samples.. 
“7o??? ed ° n i number of ta 9S recovered from cocks tagged during October and November 
U9b3; and known to have been shot in November and December (1 363 ). 
I 
NATURAL HiSTGftY SURVEY 
MAY 19 1964 
LIBRARY 
