Mrs. Doris Dodds 
Librarian 
MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
Glen C. Sanderson, Editor NATURMHISTORY SURVEY 
MAR 5 19'0 
- rct B Uyj . 
Urbana, Illinois 
February, 1970 
Vol. 13, No. 2 
1. Pheasant Population s and Lan d Use S. L. Etter, 
R. E. Greenberg 
The estimated harvest of cock pheasants on the Sibley Study Area, based 
on changes in the sex ratio, indicates that 44 percent of the available cocks 
were killed during the 1969 hunting season. The estimated harvests on the 
study area in 1962, 1963, 1964, 1965, 1966, 1967 and 1968 were, respectively, 
74, 75, 70 , 46, 53, 36, and 54 percents of the available cocks. 
During the period in which these data were obtained, hunting regulations 
varied considerably. In 1962, 1963 and 1964, three cocks were allowed in the 
bag. Two-cock bag limits were allowed in the following 5 years. Season 
lengths in 1962, 1963 and 1964 were 292, 33i and 36^ days, respectively. 
Season lengths in 1965, 1966, 1 968 and 1969 were, respectively, 29^, 30j, 45i 
and 46j days. The 1967 season was originally set for 29i days but was 
extended l4 days because of an extremely low kill resulting from large 
acreages of standing corn. 
The higher harvest in 1962, 1963, and 1964, compared with later years, 
apparently resulted from a combination of higher population levels and the 
three-bird bag limits then in effect. A comparison of the harvests for 1965 
and 1966 with those for 1 968 and 1969, 4 years when population levels and 
hunting conditions were similar, suggests that the longer seasons in the latter 
2 years had little effect on the harvest. These data suggest the tentative 
conclusion that pheasant hunting is largely self-limiting. Once the number of 
available cocks has been reduced to a certain level, the effort required to bag 
a bird apparently becomes so great that few hunters continue hunting no matter 
how liberal the prevailing regulations are. 
2. Manipulation of Pheasant Hab it at. 
G. B. Joselyn 
Available evidence suggests that unmowed backslope areas on highway road¬ 
sides adjacent to agricultural land must be kept relatively weed-free to 
prevent undesirable reactions from farm operators (MWRL 13(1) :1). With regard 
to manipulation of vegetation now most common on the roadsides, it is also 
evident that any weed control program involving spraying with 2,4-D, with a 
few crews responsible for a sizable area, has inherent difficulties which 
jeopardize its chances for success. Our work over the past 2 years indicates 
that three sprayings are probably needed to adequately control broadleaf weeds. 
Two of these sprayings can be made during the period from late April to the 
end of May when few, if any, soybeans have emerged. However, at least 
one spraying should be made after June 1, when the chances of damaging 
