Vol. 13, No. 4 
Page 2 
4. Responses of Bobwhites to Habitat Manipulation J. A. Ellis, 
D. R. Vance 
One of the problems associated with programs of prescribed burning is estab¬ 
lishment of firebreaks. We now believe that discing, in the fall, around areas 
that are scheduled to burn during the following spring is the most efficient and 
economically feasible method of establishing firebreaks. In the fall of 1969 , 
firebreaks were disced around six plots (113 acres) in the experimental management 
zone on the Dale Area. The size of the plots ranged from 2 to 64 acres, and the 
estimated cost of discing varied from $ 1-90 per acre for the 2-acre plot to $0.64 
per acre for the 64-acre plot. The costs were calculated on the basis of $12.00 per 
hour for tractor, disc, and operator. The economic advantages of burning a few 
units of large acreages rather than many units of small acreages are readily apparent. 
5- Responses of Prairie Chickens to Habitat Manipulation R. L. Westemeier 
Booming ground surveys were conducted on the Bogota Study Area since mid-August 
1969 at approximate weekly intervals (more frequently in early April 1970) during 
the first hour after daybreak, and an effort was made to determine the maximum 
number of cocks on the area. The number of prairie chicken cocks involved in booming 
activities appeared to increase gradually from late summer 1969 through the subsequent 
fall and winter. The peak count of 108 cocks on April 5 amounts to a 112 percent 
increase since the spring of 1969 , and thus surpasses previous predictions (MWRL 
13(1):3 and MWRL 13(3) : 2). The count this spring is 38 percent higher than the 
previous high made in I 963 , when this census was initiated, and 192 percent higher 
than the low year of 1 968 . A more favorable dispersion of the breeding population 
was also noted this spring, compared with 1969- In the spring of 1 969 seven booming 
grounds were found in 3 Sections on or near six sanctuaries. This spring, booming 
was observed in 12 general areas in 6 Sections and on all but 1 of the 10 sanctuaries 
at Bogota. 
6. Rabbit Management q. B. Rose 
The energy assimilated by cottontail rabbits was estimated in the same way as 
described in MWRL 13(2):4-5. 
The rabbits in the outdoor pens consumed an average of 96 grams of rabbit chow 
per day, which, with a 63 percent assimilation efficiency, represents an energy 
assimilation of 241 kilogram calories (kcal) per day. This is a greater assimilation 
than the 206 kcal per day assimilated by rabbits kept in outdoor cages. Thus, the 
difference between the 241 kcal per day assimilated by the rabbits in the outdoor 
pens and the 206 kcal per day assimilated by the rabbits in the outdoor cages may be 
assumed to be the result of the greater activity of the animals in the pens. These 
figures for energy assimilation for April are only slightly less than the correspond- 
ing figures of 260 kcal per day and 210 kcal per day for late February and early 
March, and probably reflect somewhat higher requirements for thermoregulat ion at 
between 20 F and 55 F in February and March than at between 50 F and 75 F in April. 
