Vol. 10, No. 5 
Page 2 
3- Factors Influencing Pistribution and Abundance of Pheasants W. L. Anderson 
Audio censuses of calling cocks, conducted during May, revealed that at least 
44 breeding cock pheasants were present on the Neoga release area at the beginning 
of the 1967 nesting season. The 44 cocks found is 13 percent greater than the 
number found during May 1966 (39 cocks) and 175 percent greater than the all-time 
low (16 cocks), found during May 1964. The increase noted from 1 966 to I 967 
represents the third consecutive year that the population of breeding cocks has 
increased on the area. However, the number of breeding cocks present in 1 967 was 
only 46 percent as great as the average number found during May of the years 
pheasants were experimentally released (i 960 through 1963 ). 
The persistency of the pheasants at Neoga offers continued encouragement that 
a low-density population of pheasants may eventually become established on this 
area. It seems reasonable to assume that the longer the population manages to 
subsist, the greater are the chances of developing a pheasant genetically adapted 
to the environmental conditions that prevail in southern portions of Illinois. 
4. Responses of Bobwhites to Habitat Manipulation J. A. Ellis, K. P. Thomas 
During each of the past 4 years ( 1963 - 66 ) the average size of quail coveys 
declined progressively through the prehunt (fall), posthunt (winter), and prebreeding 
(spring) censuses on both the Forbes (15-0, 9 . 3 , and 8.7 for the 4-year averages) 
and Dale (16.1, 9*8, and 8.1) areas. 
» The average covey size for the prehunt population followed the same trend as 
population density on the two areas, declining until 1965 and rebounding in 1966 . 
Harassment during the hunting season apparently influenced the size of the 
coveys in the posthunt censuses. On the Forbes Area in 1964, 7.7 quail per covey 
were recorded after 1,074 gun-hours, whereas 12.2 quail per covey were observed the 
preceding year after 410 gun-hours. 
Annual differences in covey size, as revealed by the posthunt censuses, were 
independent of population levels on the Forbes and Dale areas. The prebreeding 
covey sizes, however, were influenced apparently by factors which determined the 
preceding fall population levels. The prebreeding covey size remained low during 
1963 (Forbes, 7 . 8 ; Dale, 5-7) and 1964 (Forbes, 8.3; Dale, 6.0), increased in 1965 
(Forbes, 14.0; Dale, 14.8), and dropped in l 966 (Forbes 8-9; Dale 8 . 6 ); these 
fluctuations were inverse to fluctuations in population density the preceding falls. 
5. Responses of prairie Chickens to Habitat Manipulation R. L. Westemeier 
During the spring period of late March to mid-April, 1967 , 21 areas in 10 
counties in south-central Illinois were systematically cruised in search of booming 
prairie chickens. At least three morning surveys were made in 8 of the 21 census 
areas and at least one morning survey, under good listening conditions, was made 
in each of the remaining 13 areas. All counts were made during the first hour of 
daylight. 
A total of 179 booming cocks were found on 16 of the 21 areas surveyed. 
