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Water Area Densities 
EE 
The aerial survey indicated an 8 percent increase in the State-wide density 
of water areas over that of 1951. The average State-wide water area density in 
1952 was 6.09 per square mile compared with 5,63 water areas per square mile 
in 1951. 
The physiographic distribution of water areas was such that the highest 
density (10.41 per square mile) occurred in the James River Valley. The Prairie 
Hills and Minnesota Valley ranked next with 9.44 and 8.32 water areas per square 
mile respectively. The Missouri Hills averaged 5.36 water areas per square mile, 
and the Missouri Plateau, 3.53. 
All of the physiographic divisions showed substantial increases in water area 
densities, except the James River Valley which had a slight (5 percent) decrease. 
The percent of increase in water area density in the other areas were 29 percent in 
the Minnesota Valley, 23 percent in the Prairie Hills, 20 percent on the Missouri 
Plateau, and 11 percent in the Missouri Hills. 
Breeding Population Trends 
The average, minimum State-wide duck density was estimated to be 104 percent 
above the 1951 level. The aerial survey indicated an observed duck density of 10.96 
birds per square mile. A correction factor of 1.22 was calculated from ground 
transect data to correct the observed density for unobserved females on nests. 
Thus, the density when corrected for unobserved females indicated an average 
minimum State-wide density of 13.37 ducks per square mile, which is 104 percent 
above the 1951 estimate of 6.57 ducks per square mile. A comparison with the 1950 
density indicates the average minimum State-wide density in 1952 to be 67 percent 
higher than the 1950 density of 8.00 ducks per square mile. 
Duck densities on the ground transects in the more permanent habitat in each 
county showed a substantial increase of approximately 45 percent above the 1951 
density. Total pairs of ducks averaged 14.0 per square mile, which is 49 percent 
above the 1951 density of 9.4 total pairs per square mile. Total ducks averaged 
24.3 birds per square mile, or 41 percent more than the 1951 density of 17.2 
total ducks per square mile. The difference between the 45 percent increase in duck 
density on the ground transects and the 104 percent increase on the aerial transects 
is believed to reflect a difference in the relative stability of duck populations in the 
more permanent habitat (ground transects) compared with that over the State as a 
whole (aerial transects). 
Coots were 77 percent more abundant on the ground transects than they were 
in 1951. There was an average density of 5.5 coots per square mile, compared © 
with 3.1 per square mile in 1951. 
Waterfowl Distribu tion 

The geographic distribution of the 1952 breeding duck population is shown in 
Figure 1. The more important changes from the distribution in 1951 are: (1) an 
expansion of the usually medium to high density area in McPherson and Edmunds 
and eastern Campbell and Walworth Counties further west into Campbell and 
