Vo 1. 6, No. I 
Page 2 
occurrence of 33 , 98, and 98 percent for grasses, alfalfa, and clover, respectively. 
Hie reduced frequencies of occurrence of alfalfa and clover between June and Novem¬ 
ber can be attributed to damage of seedlings by standing water, as portions of the 
roadside ditches were flooded during July. 
3o Responses of Bchwhites an d Prairie Chickens to Habitat Manipu1 at ion 
J. A. Ellis, R. J. Ell is 
A winter census of prairie chickens conducted in Clark County during January re¬ 
vealed an estimated population of 65 birds. Only three flocks were found in the 
county and one flock near Melrose contained about 50 birds. 
This census was accomplished by interviewing three farmers in each area of the 
county where a flock of prairie chickens had been reported by high school vocational 
agriculture students during the fall of 1962 (Monthly Wildlife Research Letter, Vol. 
5, No. 11). 
4. Factor s Inf1uencinq Distribution and Abundance of Pheasants 
William L. Anderson 
The productivity of pheasants in I960, 1961, and 1962 on the Neoga area, south of 
the contiguous range occupied by pheasants in Illinois, appeared to be sufficient to 
maintain a permanent population, Table 1. In all 3 years, the increase in the num¬ 
bers of hens from spring to fall and the ratio of juvenile hens in fall to breeding 
hens in the previous spring were similar to comparable data collected from within the 
range occupied by pheasants in Illinois and indicate that average productivity occur¬ 
red on the area. The number of juveniles per adult among hens captured during the 
prehunt period was considerably higher than in se1f-maintaining populations. How¬ 
ever, it seems more likely that these exceedingly high age ratios in the prehunt pop¬ 
ulation are an indication of an unusually high rate of mortality among adult hens 
during late summer. 
Table 1. Indices of productivity of pheasants on the Neoga study area, I960, 
1961 , and 1962 (numbers of pheasants aged in parentheses). 
I960 
1961 
1962 
A1 1 
Years 
Percentage increase in numbers of hens 
from spri ng to fall 
91 
120 
111 
106 
Number of juvenile hens in fall per 
breeding hen in spring 
1.7 
1.7 
1 .6 
1.7 
Age ratios among hens in fall:juven- 
i1e per adu1t 
6.7 (46) 
3.2 (84) 
3.2 (71) 
3.7 
(201) 
► 
