CENTRAL FLYWAY 
These surveys indicate a very significant increase in the 
breeding population from 1956 to 1957 and a significant increase from 
the average of 195456 to 1957. Although no systematic water area data 
are recorded, observations indicate that these changes were directly 
related to the changes in available habitat. 
.As noted in Table 3, the most significant increases occurred 
in the blue-winged teal and shoveler indices, these species are the latest 
migrators through the sandhills. Pintails and canvasbacks also showed 
significant increases over 1956. Significant decreases were recorded 
for the gadwall, baldpate, green. winged teal, scaup, and ruddy duck 
indices; however, it should be noted that these species occur in only 
relative minor numbers. 
Table 3 - Species Composition and Trends 
3 % Change 
% of 3 from 
1957 1956 1956 to 
Eastern Central Western Total Index Index 1957 
Mallard 2,813 6,682 17,304 26,799 17.3 25,835 + 3.7 

Gadwall 1,487 1,583 2,594 5,664 3.7 7,636 25.8 
Baldpate 388 —~351 542 1,281 08 1,743 = 26.5 
Pintail 3,348 4,217 11,010 18,575 12.0 11,858 + 56.6 
G. W. Teal “ 176 - 176 ol 703 = 74.9 
B. W. Teal 23,137 28,492 27,030 78,659 50.8 30,150 +160.9 
Shoveler 3,731 2,814 7,158 13,703 8.9 5,201 4163.5 
Redhead 194 1,149 3,790 5,133 3,3 4,324+ 18.2 
Canvasback _ - 2,931 2,931 1.9 1,701 + 72.3 
Scaup 97 526 266 889 06 3,522 = 74.8 
Ruddy = 179 811 990 »6 2,107 - 53.0 
Cinnamon - - - ~ ~ 151s 

Total ° 35; 195 46, 169 (3: 436 154, 800 ~ 94, 949: + 63.1 0 

Production Data 
The first mallard and pintail broods were observed in the 
sandhills during the last week of May which indicated that the first nesting 
attempt was about average. Brood checks made July 17-19 in the eastern 
and western areas showed that of 65 broods observed, 71 percent were of 
age Class I, 13 percent of age Class I1, and 17 percent of age Class III. 
This indicated that the major hatching peak did not occur until late July. 
65 
