Vol. 12, No. 4 
Page 3 
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5* Responses of Prairie Chickens to Habitat Manipulation 
R. L. Westemeier 
In contrast to the peak count of 37 cocks at Bogota during the spring of 1968, 
weekly counts this spring indicate a flock containing at least 51 cocks--a 38 percent 
increase. A population of this size must still be considered as critically 
endangered, but this increase provides encouragement that the preservation of 
Illinois prairie chickens can ultimately be realized. 
Donations have made possible the acquisition of 1,007*3 acres for sanctuaries 
since 1962. The Prairie Grouse Committee of the Illinois Chapter - The Nature 
Conservancy has acquired 390*3 acres at Bogota in Jasper County and 320 acres near 
Kinmundy and Forbes State Park in Marion County; the Prairie Chicken Foundation of 
Illinois controls 297 acres, all at Bogota. Current negotiations by a private con¬ 
servationist should soon add a 100-acre farm near Farina to the sanctuary system in 
Marion County. In addition, the Illinois Department of Conservation is leasing 88 
ceres of grass and legumes as a holding action until an adequate refuge system can 
L-t- established in Marion County near Farina and in southwest Effingham County near 
ioogootee. Including sanctuaries, leased acreage, and a 33~acre tract on Forbes 
Park, the total land managed for prairie chickens in Illinois now includes or will 
soon include 1,228-3 acres. 
Censuses not yet completed in the Forbes Park, Kinmundy, Farina, La Clede, and 
Loogootee areas seem to indicate that the flocks in these areas are holding their 
own and that there is still time to insure their preservation. 
6. Rabbit Management Rose 
Energy consumption, energy assimilation, assimilation efficiency, and weight 
changes of caged cottontail rabbits on a diet of commercial rabbit chow or one of two 
winter foods, Rubus sp. and Rhus qlabra , were measured and compared. 
The average energy consumed per rabbit per day was 238, 49, and 57 cal/day, 
respectively, for rabbit chow, Rhus , and Rubus . Similarly, the average energy 
assimilated was 162, 18, and 10 cal/day. The average assimilation efficiencies were 
68, 32, and 19 percent, respectively. The rabbits on rabbit chow maintained their 
weight, while those on Rhus lost an average of 0.02 kg/day and those on Rubus lost 
an average of 0.04 kg/day. All the rabbits on rabbit chow survived, while three of 
four rabbits on Rubus died within 10 days, and one of three on Rhus died within 10 
day s. 
Thus, rabbits forced to subsist entirely on Rhus or Rubus , or perhaps on the 
bark of other woody plants, as during winter when the ground is covered with snow, 
will not be able to maintain their weights, and some will die. Indeed, weight loss 
and death may come more quickly in the field during winter because of possibly greater 
energy requirements at low temperatures. 
