MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
Glen C. Sanderson and Helen C. Schultz, Editors 
Urbana, Illinois 
April, 1974 
Vol. 17, No. 4 
Manipulation of Pheasant Habitat G. B. Joselyn 
Certain biases are inherent in ground counts of pheasants (spring roadside 
counts, summer brood counts) and in other indirect means utilized to estimate 
total numbers on the Sibley and Ford County Management Unit study areas each year. 
Such biases are caused by weather conditions that affect animal behavior, 
observability, or both, and by other conditions, such as status of crops, that 
affect observability. Yet the need is great for an accurate direct count of 
pheasants on these areas each year in order to evaluate trends in numbers of 
pheasants and to determine the effects of roadside management on the FCMU on 
population levels. The best means of direct enumeration is the aerial count 
conducted from a helicopter over deep snow. Although it is intended that an 
aerial count be made each year, snow conditions are seldom suitable for such an 
undertaking. During only 3 years since 1962 have snow conditions been right 
for aerial counts to be made (Table l). 
Pheasants Pheasants 
Area 
Year 
Date 
Observed 
per Square 
Sibley 
1963 
Feb. 27-28 
4,043 
112 
(36 square miles) 
1965 
March 5 
1,684 
47 
1973 
Dec. 22 
2,226 
62 
FCMU 
1973 
Dec. 22 
2,215 
11) 
(20 square miles)* 
* Includes 16 square miles where seeded roadsides occur and 4 additional miles 
contained in the area 0.25 mile around outside edge of study area. 
The count on the Sibley Study Area in I 963 coincided very nearly with the 
highest population ever experienced on that area; the count in I 965 antedated by 
2 years the lowest population on the area in the past 20 years. 
The first two counts occurred about 2 months later than the count in 1973; 
therefore, on a comparative basis, the latter count may be too high. Regardless 
of this possibility, the numbers of pheasants on the Sibley Study Area were still 
