Vo l. 10, No. 7 
Rage 3 
site. An electric fence was also built around the unplowed block of cover 
containing the nest, as a deterrent to predators. 
Since only one nest was found by use of the flushing bar, it is hoped that 
the major proportion of the nests on the Bogota Study Area in 1967 were established 
on the nesting sanctuaries or in nesting cover leased from farmers by the Illinois 
Department of Conservation. 
6. Rabbit Management j. A. Bailey, J. C. Hanson 
An analysis was made of the relationship between the weights and lengths of 
499 cottontail rabbits captured during the periods of Hay through November in 1964, 
1965, and 1966 on either the Allerton Park 4-H Area in Piatt County or the 
University of Illinois farms near Urbana. Female rabbits weighing more than 950 
grams during the months of Hay through August were excluded from this sample to 
avoid distortion of the weight - length relationship by the weights of the products 
of pregnancy. All female rabbits included in the sample could not be designated, 
after palpation, as being pregnant. 
Each animal was weighed to the nearest ounce and its length was measured to 
the nearest 0.5 cm by grasping the rabbit by the head and hind legs, extending it, 
and measuring from the tip of the nose to the tip of the hind feet. Weights were 
converted to grams, and lengths to decimeters, for analysis. The relationship 
between weight and length was analyzed by plotting the data and fitting curves 
with (1) three-point moving averages, (2) a multiple correlation with weight 
dependent upon the first, second, and third powers of length, and (3) a total 
correlation with weight dependent upon the third power of length. 
Curves fitted to the data were similar. The multiple correlation coefficient 
was 0.976 for the cubic equation W * 788.8 -463.8 (L) + 91.1(t/) - 0.4(l 3 ), where 
W “weight (g) and L = length (dm). Likewise, the total correlation coefficient 
was 0.976 for the equation W = 15-6 + 5-48 (L^), where W and L are again weight 
and length, respectively. 
Since the correlation coefficients for these two equations are equal, the 
latter, more simple equation is preferred. Solving this equation for the regression 
coefficient and rounding off the dependent variable intercept produces the equation 
5.48 = (W - 16)/L .which can be used as an index to the physical condition of 
cottontails. For example, in the present sample of 499 rabbits, any animal with 
a condition index greater than 5-48 was heavier than average for its length class. 
