Vol. 25, No. 5 
Page 3 
In future newsletters we will describe a field experiment 
the above hypothesis and the results of this experiment. 
designed 
to test 
Responses of Prairie Chickens to Habitat Manipulation, - W-66-R 
R.L. Westemeier, 
J.E. Buhnerkempe 
The concentrated distribution of the prairie chicken population at Bogota 
is a continuing concern in efforts to preserve Illinois' native pra i r i e grouse 
(MWRL 25(M:3"M• Since 1970 when pheasants became common at Bogota, 71 J2 0 
the prairie chicken cocks have been concentrated op the central 39* of the 
the P r *' r ' e S,.;,,.,) or about 5.1 km 2 (2 m, of the overall range 
(sanctuaries and^prtvate landCombined)• Near Kinmundy in Marion County there 
are essentially no pheasants, and prairie chickens were found in good numbers 
thisTpring on and near each of the 5 sanctuaries The chickens were dispersed 
from Farina to Brubaker, a lengthy range of about lA.'t km (9 mi). 
For 6 consecutive years there have been no prairie chickens on the Mark 
sanctuaries ^23 ha 57 acres) at Bogota, and this spring no chickens were found 
on ihe i! McLLck Sanctuary (32 ha, 80 acres) The McCormack tract was 
acauired in 1965 but the 1st prairie chicken cock was not present u 97 
=sarrsstysass tssz. w-SSC 
sasswarrs m-s'srss if i:- 
C sanctuaries in Marion County apparently has not limited use of the sanctua 
yThickin; On the 32-ha (80-acres) Perbix-lacey I, umt (acgu.red n 197 ) 
* r Farina the count of chickens increased from 1 cock in 1979 to zi cocks 
thii sprlng-despUethe relatively small size of the unit and the presence of 
mature hedgerows on 2 boundaries. 
„ jprars 5 s;r, 
the 1st chic i qA 7 throuah 1981. In addition to pressure from pheasants, 
SllSoSa has°iong been subjected to <-> ve-round disturbance 
by free-ranging dogs (2, ^ 
ihe "hiling-in'‘ C effect by'woody vegetation on 3 boundaries and in the center 
of the sancutary. In October 1978, 0 8 km (0.5 m of wood, ^"eerow was 
trees^and 3 several clLps of brush 
were removed from the center of the sanctuary, and all r °“ y 
of"l9827or a perhaps all factors combined. Thus, it appears that one means of 
