In an effort to determine the usage of water area types, the data has been 
worked up on a per acre basis. 
Table V - Breeding pairs by Water Area Types 

Open Wooded Total 
Number of Water Areas 154 152 306 
Acreage of Water Areas 146, 3 55.6 | 201.9 
Number of Acres Per Water Area 0.95 0.37 0.66 
Number of Mallard Pairs per Acre 1.23 1.53 1,31 
Number of B-w. Teal Pairs per Acre 71 . 68 . 70 
Number of Pintail Pairs per Acre 33 .29 32 
Number of Baldpate Pairs per Acre 18 .11 . 16 
Number of G-w. Teal Pairs per Acre 14 22 . 16 
Number of Canvasback Pairs per Acre 14 04 ~1l 
Number of All Other Pairs per Acre 25 a3 .22 
Total - All Species 2.98 3.00 2.98 
The above data indicate that there was very little difference in the amount 
of use of wooded or open areas when all species are considered. Mallards and 
green-winged teal used the wooded areas a bit heavier while baldpate and canvasback 
used the open areas more. There was very little difference in the case of the 
blue-winged teal. However, the heavy use of the wooded areas might be attributed 
to the fact that they also averaged smaller in size. It is a well known fact that 
breeding pair densities are greater on the smaller areas. The following table 
illustrates this fact: 
Table VI ~ Pairs Per Acre by Water Area Size Classes 


Open Wooded 
Size Class Pairs Per Pairs Per Pairs Per Pairs Per 
Water Area Acre Water Area Acre 
0-.5 1.01 3.99 1.18 4.11 
-6 - 1.0 3.00 3.81 1. 87 2.30 
1.1 -2.0 4.41 2.92 3.00 2.16 
2.1 -5.0 8.55 2.52 3.50 1.11 
Average 2.82 | 2.98 1.09 3.00 
For both open and wooded areas the number of pairs per acre for all areas 
up to one acre in size equals 3.72. It is interesting to compare this figure to that 
for 1,389 water areas censused in North and South Dakota in 1949 which yielded 
3.73 pairs per acre. 
There is increasing evidence each year to the effect that breeding pairs on 
the prairie breeding grounds tend to make maximum use of the available small water 
areas and spill over into less favorable or sub-marginal habitat when maximum 
capacity has been reached. The data suggests that these small (one acre or less) 
water areas were populated about to the saturation point or to carrying capacity and 
possibly the utilization of them may provide an index to the status of the population. 
