Vol. 25, No. 2 
Page 2 
Ecology and Management of Squirrels - W-66-R C. M. Nixon, 
L. P. Hansen 
The literature indicates that fox squirrel populations have 2 reproductive 
periods each yeai—l in spring and 1 in summei and that most adult females 
participate in each breeding period. Unfortunately, much of this literature is 
anecdotal or at best incomplete. We collected data from 14 breeding periods on 
a study site near Danville (see previous newsletters). Breeding rates of adult 
fox squirrels (>1.5 years old) were higher during spring (68%) than during 
summer (49%). Generally, a small proportion of yearlings had young during the 
spring (0-67%), whereas no yearlings reproduced during the fail. About 28% of 
the adult female fox squirrels that reproduced had litters during both spring 
and summer of the same year, 33% had litters only in spring, and 33% had litters 
in fall only (Table 2). Table 2 also indicates that seasonal and annual 
variability rates were high. These results are from an unexploited population 
and results from an exploited population may differ. Regardless, it appears 
that reproductive rates of individual fox squirrels are low. In next month's 
newsletter, we will look at potential causes of seasonal and annual variability 
in reproductive rates. 
Table 2. 
for which 
Frequency of breeding 
breeding histories are 
in adult female 
known for both 
fox squirrels. 
spring and fal1 
Only females 
are included. 
Year 
N 
Spring 
only 
Fal 1 
only 
Both fal1 
and spring 
Neither fall 
nor spring 
1971 
10 
3 
3 
4 
0 
1972 
19 
2 
9 
1 
7 
1973 
17 
7 
4 
1 
5 
1974 
13 
3 
4 
1 
5 
1975 
14 
2 
3 
9 
0 
1976 
14 
10 
3 
1 
0 
1977 
10 
4 
0 
5 
1 
Responses of Prairie Chickens to Habitat Manipula tion - W-66-R R.L. Westemeier, 
J.E. Buhnerkempe 
Pheasants are a serious threat to the survival of prairie chickens near 
Bogota in Jasper County, according to recent studies (MWRL 24 (11):2-3)• Capturing 
pheasants by nightlighting and removing them from the sanctuaries has been 
suggested as 1 means of control (MWRL 24(3)-3“4). How effectively capture and 
removal will control pheasants depends on the rate at which the vacated habitat 
is reoccupied by pheasants from surrounding areas. Available data indicate that 
the rate of reoccupancy would be relatively slow. 
