Vol. 25, No. 4 
Page 4 
in Wisconsin and Minnesota and the current population increases in Mar ion County, 
it seems probable that the Bogota flock would be twice the present level i 
pheasants were not a strong adverse factor. The impact of pheasants on the 
prairie chickens at Bogota may be most serious during cyclic lows. The sex 
ratio at Bogota was 1.93 cocks per hen; the high count of hens for all leks was 
only 43 compared with 33 cocks. The distribution of leks at Bogota was less 
favorable than near Kinmundy. Ninety-five percent of the Bogota flock was 
concentrated on 3 central sanctuaries, with about 1.6 
a triangle connecting the leks. Such a concentration 
cover 1nterspersion, edge effect, and opportunism ava 
Kinmundy. 
km (1 mi) on each side of 
does not allow for the 
ilable to the flock near 
Near Mt. Erie in Wayne County, 4 cocks were located 
with 2 cocks in 1981. Near Hoyleton, however, no prairie 
on either of the 2 prime mornings for locating chickens, 
located near Hoyleton in February 1981, but they were not 
the seasonal peak of booming in 1981. 
this spring compared 
chickens were found 
Three cocks were 
found there during 
has 
If one 
some 400 
assumes a 50:50 sex ratio (probably not a valid assumption), Illinois 
prairie chickens this spring, an increase of 25 % since the spring 
of 1981. 
Ecology and Management of White-tailed Deer - W- 87 -R 
C.M. Nixon, L.P. Hansen 
J.E. Chelsvig, P.A. Brewer 
Evolution has provided white-tailed deer with a social system and life.sty e 
designed to reduce predator losses and to enable deer to locate the successional 
landscapes that produce digestible forages. Man and his machines ^ve substituted 
for the ancestral predators—wol f, mountain lion, bear—that shaped the white ta 
as we know him today. 
In central and northern Illinois, seasonal changes In avallabi1ity of food 
and cover caused by planting and harvest have severely 1 united populations of 
pheasants, bobwhites, cottontail rabbits, and a host of nongame species. Yet 
these agricultural activities have not reduced the numbers of deer. Why not. 
Because the social system that evolved to succeed in prehistorical northern 
ecosystems works just as well to circumvent the drastic changes in landscape 
caused by agricultural activities. Harvest and fall plowing affect Illinois deer 
similarly as the northern winters affect deer farther north. 
Deer in northern landscapes, where winters are often severe and the timber 
wolf still coexists, typically utilize distinct summer and winter landscapes, 
^ien many mites d!itan?. Individual deer return consistently to the same summer 
range from the same winter range accompanied by the.r offspring. Young deer tu 
learn routes of migration by following the adults, and the patterns ?[ f 
are kept intact from generation to generation. Research has shown that 1 
annual life cycle of deer is adapted to avoiding predation; deer.live a generally 
solitary existence during the critical parturition and fawn-rearing period an 
