Vo 1. 20, No. 3 
Page 4 
on relatively unstable booming grounds. Likewise, success of prairie chicken 
at'togota McCorm,ck Sanctuary has generally been lowest of all the sanctuaries 
Yeattlr^i^d a ! S a Vr active t armsteads withi " about 0 .25 mile of the 232-acre 
L ! '- F K d; d McGraw com Pl e ><- The farmstead on the east side of this 
complex is the main source of dogs. Although densities of prairie chickens 
have remained highest (average of 41 cocks per 100 acres of nest cover) in 
east side^of'theVeMT Chid<enS ^ beC ° me increasi "9>y limited on the 
east side of the Field Sanctuary. One year, three young prairie chickens were 
b^a bfr^og.^ Uneate "' in thiS area ~" c ^ a rac ter i s t i c^of havingt^n h™ 
In Marion County, response of prairie chickens to the Illinois Natural 
cgr/nS^bTr , ( ' 60 r reS) ° CCUrred the same y ear the^and^was r> 
rana no dinf V 9 *'* l ° ^ preSence of numerous feral and free- 
rang.ng dogs, only one to four male prairie chickens boomed on or near this 
tract during 6 of the last 10 springs. Litters of feral dogs were found In 
bandoned woodchuck dens on three occasions on or near the Survey Sanctuary 
On four '^stances we have had close calls with packs of feral o/free-ranqi™ 
numbered as^ ah as 12^ ^^i ind ! c f ion of stacking. Such packs have 
similsr - 9 2 dogs ’ Local farmers in Marion County have related 
s.milar experiences to us-and assisted in control of such dogs. 
In V ener * ] > however, control of dogs on the sanctuaries is difficult We 
si« 
relations in the prairie chicken areas. P C 
at Rnno^^ 6 ab ° Ve reasons ' we P ,an to try electric fencing on two sanctuaries 
reduce predation TT th ' S y6ar * E,ectrIc fencing has been used to 
nhfc^ P ? d ° individual nests of sharp-tailed grouse (Pedioecetes 
^ff ecUvI v S Led t n UCk 4' n N ° rth Dak ° ta ' Als °’ a 2 ’ 00 °- m electric fence was 
? f! tC protect a nesting colony of sandwich terns (Sterna 
sa ndy.censis ) from predation by red foxes in Scotland. Thus it mav be 
possi e to control aogs and wild predators by the use of electric fences. 
with Ilectri Heat' ion ’n ^ t0 establish woven wire fences in combination 
w.tn electrification on most of the sanctuaries. Continued tresoass on th* 
dHve trucks y and y e^e h s" terS , •'? a "-[ errain vehicles, trail bikes, four-wheel- 
sh r 4td t b r ra k5 rouU„e V an„:al“ho^? 5 ' ^ that ““ ki " d fa "-"9 
* 
