Voi. 19, No. 1 
Page 3 
Thus, squirrels make little use of clear-cuts the first 2 years after cutting. 
Juvenile squirrels whose precut home ranges include areas that are subsequently 
clear-cut usually disperse or die; they do not usually move to adjacent uncut 
stands. Adults that have large portions of their home ranges affected by clear- 
cuts usually disappear, presumably to disperse or die; they do not displace the 
squirrels that live adjacent to the clear-cut areas. Adult squirrels with less 
than half of their home range affected by clear-cuts usually shift their 
activities into the uncut portions of their precut home ranges. Penetration of 
the clear-cuts by squirrels may represent the squirrels' reluctance to abandon 
totally previously established home ranges despite the extreme physical alter¬ 
ation of the sites by clear-cutting. 
Responses of Prairie Chickens to Habitat Manipulation R. L. Westemeier, 
D. R. Vance 
The old adage among ecologists, "Nothing succeeds like succession," is 
particularly appropriate in the prairie-forest transition zone of southern 
Illinois. Invasion of grasslands on prairie chicken sanctuaries by woody 
vegetation can be serious in as little as 3 years after land acquisition, 
cessation of row cropping, and seeding with a grass-legume mixture. In most 
instances, the speed of invasion by woody plants depends on the proximity of 
seed sources. One of the most rapid shrub invaders in our grasslands is 
multiflora rose ( Rosa multiflora ). Rapid tree invaders include ash ( Fraxinus 
spp.), maple ( Acer spp.), and cottonwood ( Populus deltoides ), which have seeds 
that are readily disseminated by wind. Other problem species include mulberry 
(Morus spp.), honey locust ( Gleditsia triacanthos ), hawthorn ( Crataequs spp.), 
Japanese honeysuckle ( Lonicera japonica ), and trumpet creeper ( Campsis radicans ). 
Desirable woody species include wild black cherry (Prunus serotina ), oaks 
(Quercus spp.), dogwood ( Cornus racemosa ), and dewberry (Rubus flaqellaris ), 
but even these species should be limited to scattered trees, clones, or patches 
on prairie chicken sanctuaries. Some of the above species have shortened the 
longevity of redtop meadows on sanctuaries from an average of about 8 years to 
4 or 5 years. Invaded fields can be remedied most expeditiously by plowing, 
cropping 1-2 years with soybeans plus herbicides, and then reseeded to nest 
cover. However, such short rotations on the limited sanctuary acreage reduce 
the amount of nest cover available on an annual basis. Our goal must be to 
maximize the available nest cover on an annual basis from about 65 percent of 
the sanctuary acreage under the current management program to about 90 percent, 
as explained in the last newsletter (MWRL 18(12):2-3). 
Some fields are not suitable for control of succession by plowing and 
reseeding. Such areas include steep slopes and fields in which prairie 
restoration is under way. About 143 acres of sanctuary land were useless to 
prairie chickens at the time of acquisition and, for the most part, are still 
useless as nest-brood habitat because of the presence of woodland and brush. 
Other sanctuaries, though free of solid stands of woody cover, are surrounded 
by wooded fencerows or are intersected by dendritic draws. Linear distributions 
