69 
Table III - Trends in Production and Species and Age-Class Composition of 
Broods, 1951-52, Determined by the Road-Count Method 
(12 transects - 50.4 square miles) 


1951 1952 
Species July 9 - 22 July 8 - 19 
Broods Species Percent Broods Species Percent 
Mallard ‘ 91 23.7 113 39.3 
Pintail 29 7.6 27 9.4 
Baldpate Z26 6,8 13 4.5 
Gadwall 3 0.8 4 1,4 
Shoveler | 11 2.9 6 2.1 
Blue -winged teal 49 12.8 28 9.8 
Green-winged teal 6 1,6 4 1.4 
Canvasback 73 19.0 46 16.0 
Redhead 20 5.2 12 4.2 
Ruddy duck 24 6.3 10 3.5 
Lesser scaup 20 5.2 5 1.7 
Others 32 8.3 19 6.6 
Total 384 287 
Age Class 
I 177 46.7 110 39.0 
II 86 22.7 61 21.6 
III 116 30.6 111 % 39.4 
379 (+5 unaged) 282 (+5 unaged) 
Broods per sq. mile 7.6 5.7 
Trend -- -25.6 percent 
Brood Sizes 
Average brood sizes by age classes are givenin Table IV. Some 
limitations in the comparison of average brood sizes are reported in Special 
Scientific Report: Wildlife No. 13 (1951), p. 58. 
Table IV - Average Brood Sizes by Age Classes, 1949-1952 
Class I Class II Class III 
Year Av. Size No. Broods Av. Size No. Broods Av. Size No. Broods 
1949 7.0 329 7.0 138 6.5 130 
1950 6.5 173 5.8 71 6.3 86 
1951 6.8 302 6.5 128 ge 99 
1952 T.2 166 6.4 66 7.3 67 
Nesting Success 
There was evidence in the form of deserted nests that receding water 
levels were adversely affecting the nesting success of over-water nesters. Seven 
