Vo 1. 14, No. 5 
Page 3 
# 
» 
was particularly evident in the small-grain stubble fields. The first 
year (1967) resulted in a luxuriant stand of oats and in a good stand of 
lesser ragweed ( Ambrosia artemisiifolia ) after the oats were harvested. 
In contrast, in 1970 the oats crop was poor, and lesser ragweed in the 
stubble fields was replaced by green foxtail ( Setaria viridis ), crabgrass 
(Diqitaria ischaemum ), and buttonweed ( Diodia teres ). The ragweed-stubble 
complex not only afforded ideal night-roosting cover but was also an 
abundant source of a highly utilized food item. 
5* Responses of Prai rie Chickens to H abi tat Manipulation R. L. V/estemeier 
Results of booming ground surveys conducted in nine areas in seven 
counties of south-central Illinois in the spring of 1971 revealed a total 
of 222 prairie chicken cocks. The 1 59 cocks censused at Bogota comprised 
72 percent of the statewide total and showed an increase of 47 percent 
since the spring of 1970. Five cocks were censused for the first time 
this spring near Bible Grove in Clay County. The remaining 58 cocks on 
seven areas outlying the Bogota Area represent a loss of 23 percent since 
last spring. Losses of 50 percent or more occurred at Kinmundy-Forbes 
Park (13 cocks to 6 cocks). La Clede (3 cocks to 1 cock), Loogootee (17 
cocks to 8 cocks), and Hoyleton (4 cocks to 2 cocks). The Farina Area 
continued to hold the largest flock outside of Bogota, but the count at 
Farina was 14 percent lower than last spring (28 cocks to 24 cocks). As 
in the past two springs, four cocks were found at Fairman in western 
Marion County. A relatively stable population was also noted near Mt. 
Erie in l/ayne County, where the counts were 12 cocks in 1970 and 13 cocks 
in 1971. 
Two sanctuaries totaling 320 acres (Survey 160 and Butler 160) are now 
established in Marion County in the Kinmundy-Forbes Park Area, and one 
tract of 140 acres (Lacey 100 and a new acquisition of 40 acres) is now 
available in the Farina Area. Booming cocks and hens were observed this 
spring, for the first time since acquisition, on both the Butler and Lacey 
sanctuaries. Although the prairie chicken flocks near these sanctuaries 
are at a critically low level, their prompt recovery seems likely because 
of the responsiveness demonstrated by this native grouse at Bogota in 
Jasper County. 
6. Rabbit Managemen t G. B. Rose 
Energy consumed per day (MWRL 13(2):4— 5) by cottontail rabbits during 
the period June 1970 through May 1971 was negatively correlated with 
ambient temperature. The correlation was highly significant for rabbits 
in outdoor cages and for rabbits in outdoor pens. The regression equation 
for the caged rabbits is Y = 88.75 - 0.449X, and for the penned cottontails 
is Y = 124.50 - 0.503X, when X is the mean air temperature for the experi¬ 
mental period and Y is the number of crams of commercial rabbit chow con¬ 
sumed per rabbit per day. 
Daily energy consumption per gram of body weight is also negatively 
