Vol. 9 , No. 9 
Page 7 
and .? 5 '? P ercent have been cover dominated by legumes. The comparative 
availability of grassland and leguminous acreages, in percent of the total land 
area has ranged from nearly equal availability in 1 963 to 11.6 percent grassland 
7*5 percent legumes in 1965 * Considerably more legumes than grassland have 
currently been available to nesting hens, which tends to strengthen the concept 
that grasses are preferred. 
Nevertheless, the highest density of nests (2.4 acres per nest) documented 
since the project began occurred in 1964 on the Yeatter Sanctuary in a 19.1-acre 
field of redtop which also had a conspicuous admixture of red clover. Significantly 
the clover provided part of the concealment or was near seven of the eight nests 
round in the field. 
From the cultural standpoint, as well as from the standpoint of nesting ecology, 
egumes are desirable in stands of grass because they can utilize atmospheric 
nitrogen through the medium of symbiotic nitrogen-fixing bacteria. The nitroqen 
ultimately becomes available to the grass. In 1 966 , about 150 acres of grass - 
legume mixtures and 100 acres of nearly pure stands of grass have been or will be 
?! m ’ shed on the 2 57 acres acquired as nesting refuges by the Illinois Chapter- 
The Nature Conservancy. 
Table 4. Dominant cover types at the 
nest searches on the Bogota StuHy 
sites of 
in 1966 
prairie chicken nests 
and during the 1963-66 
found during 
period. 
1966 
1963-66 
Cover Type 
Acres 
Searched 
Nests 
Found 
Acres 
per Nest 
Acres 
Searched 
Nests 
Found 
Acres 
per Nest 
Grasses 
Legumes 
Green Wheat £■ Rye 
Weeds 
211 
75 
0 
20 
6 
0 
0 
2 
35-2 
10.0 
915 
490 
178 
20 
41 
2 
0 
2 
22.3 
245.0 
10.0 
Totals 
306 
8 
1,603 
45 
CO r! r ^ eS in the fie,ds {n which prairie chicken nests were 
FTrf^ 67 reS 'dents, Bogota Study Area, in 1966 , and during the 1963-66 
Possibly as many as 14 nests were in leguminous cover in 1966 , but since two 
reports for one field varied from 6 to 13 nests, the more conservative number is 
used. 
