
‘CENTRAL FLYWAY 
Table L - piysiveWvapiic ‘Distribution of the Breeding Waterfowl Population and 
1955 - 1956 Trends  - Canin 
1955 - 1956 Trends Continued - 
Estimated Minimum Percent of State-wide 
Physiographic Population Population 
Division 1955 1956 1955 1956 Change 
Minnesota Valley 8,000 13,000 2% 2%. - 
Prairie Hills 88,000 134,000 24% 24% = 
James River Valley 130, 000 179, 000 36% 31% - 5% 
Missouri Hills 45,000 67,000 13% 12% - 1% 
Missouri Plateau 89,000 178,000 25% 31% + 6% 
State-wide 360, 000 571,100 100% 100% 
Sr 
Table II- Comparisons of Minimum Species Breeding Populations in South Dakota 
1955 1956 | 
Minimum . Minimum. Percent 
Species Population Population Change Change 
Blue-winged Teal 171, 900 275, 100 + 103,200 + 60% 
Pintail 39, 600 36, 600 < 3,000 - 8% 
Mallard 58,000 54,600 7 3,400 - 6% 
Shoveler 39,400 73, 300 + 33,900 + 86% 
Gadwall 16,500 35,100 + 18,600 +113% 
Redhead 6,400 19, 400 + 13,000 +203% 
Ruddy Duck 8,900 9, 700 + 800 + 9% 
Scaup | 13, 800 38,100 + 24,300 +175% 
Canvasback 2, 300 3, 000 + 700 +.30% 
Baldpate 3,100 19, 400 + 16,300 526% 
Green-winged Teal 100 8,000 + 5,900 +5900% 
Wood Duck - - - - 
Ringneck r | 800 + 800 - 
Total 360,000 571,100 + 211,100 + 59% 

Production Indices - 
The 1956 mid-July survey indicated an average observed brood density 
of 0.336 broods per square mile (Table III). This is 17 percent below the 1955 
average of 0.406 broods per square mile, and 44 percent below the 1953-1955, 
three-year average of 0.599 broods per square mile. 
57 
