MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
T. G. Scott, Editor 
Urbana, Illinois 
February, 1961 
Vol. U, No. 2 
W-30-R-ll* R. F. Labisky, R. I. Smith 
A final analysis indicates that 92.0 per cent of the cocks were removed 
from the pheasant population on the Sibley area by hunters during the I960 
hunting season. The estimate was based on the change between the pre-season sex 
ratio of U9.3 per cent cocks, obtained from'the night-light trapping of 189 
pheasants during October and early November, I960, and the'post-season ratio 
of 21.7 per cent cocks, obtained from roadside counts of U,ll8 birds during 
January and February, 1961. The harvest of cocks on the Sibley area during 
previous hunting seasons was 99.U, 12,U, UlwO, and 92.9 per cent in 1996, 1997, 
1998, and 1999, respectively. 
W-U2-R-10 R. D. Lord, Jr. 
Much of this month was spent in writing the manuscript for the cottontail 
bulletin and analyzing activity data. Hox-rever, the prototype model of a tran¬ 
sistorized radio transmitter to be placed on rabbits to accurately study home 
ranges was developed by Bill Cochran for this project. This prototype has a 
range of about \ mile and weighs only 90 grams. Cochran is now constructing a 
directional finding receiver for use with the transmitters. 
A check of rabbit damage to trees on the U—H study area showed that 
damage was greater this year than in any of the past four winters. This was 
probably due to the lack of artificial food being supplied this winter plus a 
larger winter population due to no hunting on the area. 
W-99-R-9 F, C. Bellrose 
The initial aerial census of waterfowl found in Illinois during the spring 
season was made on February 2U. Even at this early date the spring migration of 
waterfowl was underway as indicated by the appearance of several species not found 
on the winter inventory taken in early January. 
Of the early migrants^ pintails were the'most common, numbering over 
6,000, followed in order by U,000 canvasbacksj 1,100 ring-necked ducks, and 
100 redheads. A few small flocks of widgeons, gadwalls, and green-winged teals 
suggested that these species were just beginning to arrive in the state. This 
NATURAL 
UICTHDV CHim/c* 
