NORTH DAKOTA, SOUTH DAKOTA, AND 
en 
MINNESOTA - Continued 

Breeding Population Indices 
In the Tri-State area as a unit there was a decrease of 
56 percent in breeding population this spring which parallels the 
decline in water areas (- 60%). However, among the three States 
there were decreases of 64 percent and 68 percent in the States 
of North Dakota and South Dakota respectively, while there was an 
increase of 94 percent in the breeding population index in 
Minnesota. The increase in Minnesota occurred in spite of a 
decrease in water areas. The habitat in Minnesota is character- 
ized by a larger number of deeper, more permanent lakes, which. 
have probably attracted birds from the drought areas to the west 
where fewer water areas of this type are present. | . 
The coot index increased greatly in the Tri-State area 
(/ 192%) with most of the increase occurring in Minnesota. 
This increase could be misleading as coot were observed concen- 
trated in numbers on large water areas. The same thing was true 
with puddle ducka. This was at a time when nesting should have 
been well underway. 
The breeding population data for the three States for 
1958 and 1959 are presented in Table 2. 
Production Indices 
The drastic reduction in available water areas before 
and during the nesting period apparently influenced the numbers 
of broods produced. Brood Sizes were small. TJTate nesting 
activity was verified by the number of Class I broods observed 
in and outside the limits of the transects. Very few divers 
were observed throughout the area covered. Larger bodies of 
water held flocks of waterfowl that did not appear to be nesting, 
Stock ponds and dugouts in the western strata that held 
pairs of waterfowl during the May survey and were still holding 
water in July, were barren of either adult or broods during the 
July survey. This leads to speculation as to what extent areas, 
especially "dugouts," contribute to waterfowl reproduction, 
The production data collected in the three States are 
summarized in Tables 3, 4 and 5. 
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