Vo 1. 22, No. 3 
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fields with low nest success. This relationship held true regardless of annual 
variation in cover density. For example, fields with 50 percent nest success 
in 1977 (the densest cover of 1977 ) had density values nearly identical to 
those of fields without nests in 1976 (the least dense cover of that year). 
Further evaluation of nest density versus nest success will be necessary 
before we can conclude that the intermediate cover is, in fact, “predator- 
resistant." It may be that nest density is a more Important factor in protecting 
nests from predators than vegetation height and density. 
Table 2. Density (percent occurrence) of vegetation related to nest success of 
prairie chickens, 1976-1978. 
Height class (cm) 
1-5 
6-10 
11-15 
16-20 
21-25 
26-30 
X (to 30 
1976 Fields 
Without nests 
69.4 
36.8 
16.5 
10.3 
5-6 
3.6 
23.7 
With nests, success £50% 
71.1 
42.9 
24.7 
15.1 
9-3 
7-4 
28.4 
With nests, success <50% 
82 . 1 
53.1 
27 .O 
17.9 
10.2 
6.7 
32.8 
1977 Fields 
Wi thout nests 
56.5 
28.4 
13.9 
7-4 
4.4 
3-2 
19.0 
With nests, success >50%, 
61.2 
30.8 
14.2 
6.9 
4.0 
2.8 
20.0 
With nests, success <50% 
69 . 1 
35-4 
17.7 
9.9 
5-3 
3-7 
23.5 
1978 Fields 
Without nests 
67-7 
24.7 
9-3 
3.3 
3.5 
3-4 
18.7 
With nests, success 250 % 
77.8 
30.7 
9-1 
5.1 
3.3 
3-3 
21.6 
With nests, success <50% 
71.2 
38.6 
18.6 
8-9 
5.7 
6.1 
24.8 
1976-78 Fields 
Without nests 
64.5 
32.3 
14.7 
8.4 
4.9 
3-4 
21.4 
With nests, success >50% 
68.4 
35.5 
17.2 
9.7 
5-9 
4.7 
23.6 
With nests, success <50% 
75.8 
44.6 
22.3 
13.3 
7-7 
5.8 
28.2 
