Vol. 7i No. 5 
Page 3 
Loss of conservation reserve acres during 19&3 and 1964 »*ll I probably have an 
adverse effect on prairie chicken numbers in Illinois. Unless depleted nesting 
cover is replaced without delay, it appears certain that prairie chickens soon will 
become extinct in most sections of the state where they are now found. 
Table 2. Federal conservation reserve contracts in six counties which support the 
largest numbers of prairie chickens in Illinois*. 
Number of 
Effective 
Contracts 
County 
1963 
1964 
1965 
Clark 
52 
11 
1 
Clay 
125 
28 
1 
Effingham 
21 
8 
0 
Jasper 
72 
18 
3 
Mar ion 
64 
20 
6 
Wayne 
261 
81 
35 
Total 
595 
T55 
*Based on census made in 1962 (see Monthly Wildlife Research Letter, November, 1962.) 
Objectives of game management practices employed on the Dale and Forbes areas 
are to increase the populations of quail and to provide quality hunting. Quality 
hunting requires that the distribution of quail over the managed areas be relatively 
uniform: the habitat plantings should, as they mature, produce a pattern of dis¬ 
tribution of quail that approaches uniformity as opposed to aggregated or random 
distributions. Measuring the spatial relationships among quail coveys on the areas 
is one way to gauge the effectiveness of management practices in creating a pattern 
of uniform distribution. The technique developed by Clark and Evans (1954), employ¬ 
ing the mean distance between nearest neighbors to measure spatial relationships 
among populations, was used to determine the distributional patterns of quail on 
the areas. The coveys of quail located on the two areas during the prehunt census, 
conducted during the first 2 weeks of November 1963, were used as a basis for 
determining the patterns of distribution. The locations of coveys flushed during 
the census were plotted on maps, and the distance from each covey to its nearest 
neighboring covey was measured. These data were fitted into formulas derived by 
Clark and Evans (1954:447), and R values were as follows: 
R * r A , r A = £ r , r E = 1 
r E N 2 £ 
where N = the number of measurements of distance taken in the observed population 
or sample 
r = the distance from a given individual to its nearest neighbor 
£ = the density of the observed distribution expressed as the number of 
individuals per unit of area 
r A » the mean of the series of distances to nearest neighbor 
r 
E * the mean distance to nearest neighbor expected in an infinitely large 
random distribution of density £ 
R = the measure of the degree to which the observed distribution departs from 
random expectation with respect to the distance to nearest neighbor. Values for 
these symbols for the Forbes and Dale areas are shown in Table 3- 
