Comparison of Waterfowl Breeding Populations and 
_Water Areas in South Dakota = 1950 to 1958 
Percent 1950=1956 Percent 
_Average : Difference 

Population Index 399,300 484,519 1: 21.4 660,700 ~ 28626, 
Ponds/sq. Mie 5.04 3265 - 27-5 4.8 “_ ono 
Ducks/ sq. mie 5634 6.6 ~ 9.26 - 28.7 
Cease ras 

Production Indices 
The observed brood density measured in broods per square mile is 
above 1957 by 25% (0.4 to 0.5) but still below the 19531956 average of 
0.533 broods/sq. mile. The number of July water areas per square mile has 
also increased from 1957. It is impossible to demonstrate this precisely 
because of differences in strata boundaries existing between the State 
survey of last year and the survey of 1958. However, the increase is 
believed to be approximately 50% in eastern South Dakota. 
The late nesting index indicates a large number of broods yet 
to come off the nest. Apparently this July survey was conducted below the 
peak of hatching and about 60% of the broods were yet to be produced. 
Blue-winged teal will compose over 40% of these potential later broods. 
South Dakota + July Survey 
Brood Index 
Stratun 1 Stratum 2 Stratum 3 

5,72 17,654 \ 14,661 
Total 38,027 (Square miles) 
broods/sq. mi. & 0.51 

72 
