MONTHLY WILDLIFE RESEARCH LETTER 
Department of Conservation and Natural History Survey, Cooperating 
T. G. Scott, Editor 
Urbana, Illinois 
April 19 £8 
Vol. 1, No. U 
W-30-R-11 W. R. Hanson, R. F. Labisky 
The report on the cover requirements of pheasants on the Sibley area 
was completed. During the period of initial nest establishment in 1957, 52.It 
per cent of the 132 feeding pheasants observed were associated with forage-crop 
cover, although such cover made up only 27.9 per cent of that surveyed. Ploxiing 
made up 33*3 per cent of the area during spring and was frequented by 33*6 per 
cent of the 156 loafing pheasants observed. Heavily pastured or lightly pastured 
forage crops were frequented more often than moderately grazed forage crops. In 
August, 67*1 per cent of the 93h feeding pheasants were associated with woody 
cover; in January, only 65*8 per cent of the 307 loafing pheasants were associated 
with such cover* Self-established clumps of native woody plants were used more 
during both of these seasons than were hedges of osage orange or multiflora rose* 
The occurrence of warm, clear weather in early April triggered an increase 
in the sexual activity of pheasants on the Sibley area. Cock crowing counts in¬ 
creased from 234.8 calls per 2-minute stop in early April to 35*7 calls per stop 
in late April* Decreased tolerance among cocks early in the month resulted in the 
break-up of cock groups, and movement activities among hens also increased during 
this period. Harem formation was common by midmonth* Hens first exhibited breed¬ 
ing displays to cocks about midmonth, but copulation was not frequent until April 
20-25» Early nests were already established by April 15* 
Few cock territories have been established during the current breeding 
season, whereas territories were common by this time in 1957* Large breeding dis¬ 
play areas, often 100 acres or more in size, with indistinct boundaries have tended 
to replace cock territories. The display areas are often frequented by several 
cocks (some with harems), and conflicts between cocks are common, although there 
are no defined boundaries of defense. The population of hens in 1957 and 1958 was 
nearly the same, but cocks comprised 36*1 per cent of the pre-breeding population 
of pheasants in 1958j compared to only 19*0 per cent in 1957* These observations 
indicate the inability of cocks to defend territories effectively and to maintain 
harems of hens successfully under conditions of high densities of cocks. 
W-U2-R-7 R. D. Lord 
To determine the relationship of food to mortality and condition of 
cottontail rabbits in winter, a constant supply of commercial, balanced-ration, 
rabbit food was maintained in feeders distributed at the rate of one for every 2 
OCT 9 1959 
NATURAL 
HISTORY SURVEY 
LIBRARY 
