MONTHLY WILDLIFE RESEARCH LETTER 
^ Department of Conservation and Natural History Survey, Cooperating 
Glen C. Sanderson and Helen C. Schultz, Editors 
Urbana, Illinois March, 1 965 Vol 8, No. 3 
1 . Pheasant Popu1 at ions and Land Use S. L. Etter 
An aerial census of the prebreeding population of pheasants on the Sibley 
Study Area on March 5, 1965, resulted in a count of 1,684 pheasants, an average of 
47 per square mile. These data represent a 58.3 percent decrease from the 4,043 
pheasants (112 per square mile) observed during an aerial census of the area on 
February 27-28, 19S3* The absence of sufficient snow cover prevented a census in 
the spring of 1964. 
The low prebreeding population in 1965 appears to be largely the result of the 
low rate of production in 1964 (Monthly Wildlife Research Letters, September and 
October, 1964). On the basis of a comparison of the aerial census data and the 
fall population estimates for both years (Monthly Wildlife Research Letters, 
January, I 963 and 1 965 )» it appears that the winter mortality rates were essentially 
the same in 196 3 and 1 965 . 
A significant portion of the winter mortality in I 965 may have occurred during 
the snowstorm of February 24-25, after which 19 dead pheasants (4 cocks and 15 hens) 
^ were found by project personnel. All these deaths appeared to be directly or 
indirectly attributable to the high winds and blowing snow. In view of the small 
number of carcasses usually found, it seems likely that many pheasants died during 
this storm. 
2. Manipulation of Pheasant Habitat G. B. Joselyn 
In I 963 , estimated dates of nest establishment were obtained from 21 of the 
44 pheasant nests established on seeded roadside plots (Table 1). Peaks of nest 
establishment occurred during the weeks of May 6 -19 and June 3-16; approximately 
24 percent (10 nests) of the 21 nests were started each of these periods. By June 
3, slightly over 57 percent (12 of 21 nests) of all nests of known dates of estab¬ 
lishment on seeded plots had been initiated. 
Accurate data on establishment of nests were obtained from 17 of the 68 nests 
found on the seeded plots in 1964. As in 1 963 , peaks of nest establishment on 
seeded plots appeared to occur during the weeks of May 6 -19 and June 3-16, but nest 
estab ishment in 1964 apparently had a slightly greater spread over the entire 
summer than in 1963, with a greater percentage of nests established at later dates. 
Thus, a lower percentage of the established nests had been started by June 3 in 
9 (47 percent, 8 of 17 nests) than by the same date the year before. Also, a 
higher percentage of nests were initiated after July 1 in 1964 (nearly 18 percent, 
3 of 17 nests) than were initiated after July 1, 1 96 3 . 
1..' “i S'Jfliitif 
APR 7 1965 
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