Vol . 12, No. II 
Page 3 
nests found on the Yeatter Sanctuary were placed at a mean distance of 243j^7 
yards from the booming ground in a radial pattern similar to those on the 
McCormick Sanctuary. 
The mean distance of 229+16 yards for the 20 nests associated with the four 
booming grounds thus strengthens the concept of a preferred zone for nesting. In 
95 percent of similar situations involving booming grounds surrounded by nesting 
cover, the mean distance between a ground and its associated nests should range 
between 213 and 245 yards. Curiously, none of the four grounds described was on 
a traditional booming site and in no instance were large numbers of cocks 
involved. Three of the four grounds were categorized as booming grounds of 
uncertain status because of (1) the small number of cocks involved and (2) the 
irregularity of their presence from day to day and from time to time on any 
given morning. 
6. Rabbit Management G. B. Rose 
The annual fall censusing of cottontail rabbits on the 100-acre (40-hectare) 
4-H Area at Robert Allerton Park is being continued this fall, the 14th successive 
year. One hundred six rabbits were trapped and ear-tagged, and the tails of 87 
were dyed, during a 10-day period at the beginning of November. 
On November 22, Or. H. H. Shoemaker's wildlife management class helped 
conduct a drive through the area, during which a record was kept of the number of 
observations of rabbits with dyed and with undyed tails. A Lincoln Index estimate 
of the population for November, based on the numbers of marked and unmarked 
rabbits seen, was 288 rabbits on the study area. 
Several population estimates were calculated from the capture and recapture 
data. The Schnabel (short form) estimate is 149 animals; the geometric maximum 
likelihood estimate (MLE-G) is 282; and the maximum likelihood estimate from a 
regression of the logarithm of the number of individuals in a frequency class on 
frequency of capture (MLE-R) is 278. The MLE-R is regarded as the best method 
of estimation (MWRL 12(10) :3)• 
The Schnabel, MLE-G, and MLE-R estimates are only slightly smaller than the 
corresponding estimates for October 1969 U57> 288, and 279» respectively). An 
MLE-R estimate for November of the 131 rabbits that were handled in October was 
129; thus, mortality during the month of October has been negligible. 
