MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
T. G. Scott, Editor 
Urbana, Illinois 
July I960 
Vol. 3, No.7 
W-30-R-13 R. F. Labisky 
The standardized counts of pheasant broods taken on the Sibley area during 
July, I960, indicated a 57.7 per cent increase in the production of broods when 
compared to similar counts taken during July, 1959. The number of broods observed 
along 320 miles of roadside transect increased from 52 broods in 1959 to 82 broods 
in I960. The mean age of the broods was 5.8 and 4.7 weeks in 1959 and i960, 
respectively. 
W-42-R-10 Rex Lord 
Because of the discovery of a significant positive correlation between 
litter size and latitude in cottontails, a collection of rabbits was made in 
Illinois at three widely separated points in the northern, central, and southern 
parts of the state. To reduce the effect of habitat on age ratios and insure 
a representative sample, collectors confined themselves to roadsides between 
agricultural fields consisting mostly of corn, soybeans, and hay. Adequate 
samples were obtained from the southern and central areas, but difficulties were 
encountered in the northern area which may make it impossible to obtain the 
necessary basic information for that part of the state. 
W-55-R-4 
F. Bellrose 
The project was inactive during July. 
W-56-R-4 G. Sanderson 
U. Meyers 
During the first half of July, 1959, 48 raccoon- and 47 opossum-cap¬ 
tures were made in 900 trap-nights on the Allerton Park study area, or 19 trap- 
nights each per raccoon and opossum caught. During a similar period this year 
three raccoons and nine opossums were caught in 518 trap-nightsr 173 trap- 
nights per raccoon and 58 trap-nights per opossum. These data suggest that the 
AUG 9 1960 
NATURAL 
HISTORY SURVEY 
LIBRARY 
