MONTHLY WILDLIFE RESEARCH LETTER 
Vol. 1, No, U 
Page 2 
acres over the study area. The feeders were checked for use after every tracking 
snow, and it was found that at least 86 per cent of them had been visited by 
rabbits. Rabbits were censused in the late fall and late winter and the inter¬ 
vening mortality determined. Close agreement was found between this mortality 
and that of the previous year. The average early winter and late winter weights 
were compared and checked with the previous years’ x^eights, and the weights of 
the rabbits in late winter were found to have been significantly heavier the year 
of feeding. A comparison was made of damage done to planted trees for both years, 
and the extent of damage was found to be significantly lower during the year in 
which artificial feeding was practiced. 
The rabbits used the food and received benefit from it, yet mortality 
occurred at the same rate as that of the previous year. Food apparently was not 
the critical factor in winter mortality. Eecause the mortality rate was the same 
for both years even though the population densities varied 22 per cent it appeared 
that the etiological agent was density independent. 
Reproduction seems to be up this year over last year. In March a sample 
of 6l rabbits showed 96 per cent of the females pregnant as opposed to 7h per cent 
last year. In April, a sample of 63 rabbits showed 79 per cent of the females 
pregnant compared to 36 per cent last year. The average litter size has remained 
about the same for both years, h»3 young per pregnant female in March and 5*6 
young per pregnant female in April, 
W-52-R-3* P* Vohs, R. Conder 
Cottontail rabbits continued to utilize two of the three wide-row fields 
much more intensively than the adjacent control fields. Pellet census data show 
0,69 pellets per square foot and 0.29 per square foot at the Bradley wide-row and 
control fields respectively. At the Little Grassy area, 0,95 pellets were located 
per square foot in the Korean lespedeza-red clover-orchard grass wide-row field, 
0.20 in the control field, and 0.19 for the millet-yellow sweetclover-ryegrass 
interseeded wide-row field. No spring growth of the yellow sweetclover or ryegrass 
was evident and food and cover was equal to that provided by the control plot. 
W-55-R-2 F. Bellrose 
Three waterfowl population surveys were made in April on the 8th, llpth, 
and 30th. In general, waterfowl populations were appreciably lower than during 
the same period in 1957. Only the lesser scaup in the Mississippi Valley and the 
shoveler appeared in greater numbers this April. During March, 1958, the spring 
waterfowl flight was 2 x-reeks behind schedule, but dxiring the first half of April 
the flight accelerated to seasonal averages as the colder than normal x^eather 
became warmer than normal. 
^Southern Illinois University, Cooperating 
