MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
T. G. Scott, Editor 
Urbana, Illinois 
October 1958 
Vol. 1, No. 10 
W-30-R-12 R. F. Labisky 
Two hundred and eighty-three pheasants were trapped by night-lighting, 
marked with plastic back tags, and released on the Sibley area during October. 
The trapping and handling of these birds resulted in the loss of only four (l.U 
per cent). Eleven (3.9 per cent) of the birds had been trapped and marked 
during the fall and winter periods of 1956-57 and 1957-58. The age ratio among 
the trapped pheasants was 3.9 young per adult hen; pre-hunt age ratios of 1956 
and 1957 were 6.8 and 3.2 young per adult hen, respectively. These data indicate 
that productivity was somewhat higher during the 1958 nesting season than 
during the 1957 nesting season but was still far below the 1956 rate of pro¬ 
ductivity. 
W-U2-R-8 R. D. Lord 
The monthly sample of rabbits indicated that reproduction has been 
terminated for this year. Trapping, marking, and releasing of rabbits on the 
two Robert Allerton Park study areas has almost been completed. So far, 218 
captures were made in 5,830 trap-nights on the U-H study area or 0.037 captures 
per trap-night. Of these, 119 were newly caught rabbits, 88 were recaptures 
from this year, and 11 were recaptures from last year. On the Sanctuary study 
area the population seems to be quite low this year; only 33 captures have been 
made in 3,000 trap-nights or 0.011 captures per trap-night. Of these, 23 were 
newly caught rabbits, 7 were recaptures from this year, and 3 were recaptures 
from last year. 
The early-morning and spotlight censuses for October on the Sibley 
study area are very comparable to last year*s. No rabbits were seen in the 
early-morning census and only 0.29 per mile in the spotlight census. Fall has 
been found to be a poor season for any kind of roadside census for rabbits. 
W-55-R-3 F. Bellrose 
Five aerial censuses of waterfowl populations were made in the Illinois 
and Mississippi River valleys in October. Censuses were made on the 1st, 11th, 
16th, 22nd, and 29th. 
OCT 9 1959 
NATURAL 
HISTORY SURVEY 
LIBRARY 
