93 
case of mallards and puddlers in general, some effects of predators can be observed. 
An important factor in this study is that these figures represent the first nesting 
attempt. Later nestings are more difficult to find because of the growth of nesting 
cover as the season progresses. It could be expected that nesting success would be 
higher in the later nestings for the reason that they would be less vulnerable to 
predation. 
Tables [I] and [V are self-explanatory. An interesting point appears in the 
accurate counts of the Class I broods on these two tables. The Class I broods 
observed on the August 3 count are apparently the results of second or late nesting 
efforts. In mallards and blue-winged teal, the averape brood size is smaller on the 
August 3 count than it was on the July 16 count. This coincides with the idea that the 
clutches of second nesting attempts are usually smaller than the first. nestings. 
These tables also indicate the late appearance of ruddy, baldpate, and gadwall broods. 
Tables V and VI show the broods by age classes at the time the two brood 
counts were conducted. By computing the ages of the broods in Class I from Tables 
III, IV, V and VI, the peak of the hatch can be calculated. Tables V and VI also 
indicate trends in production on the habitat types of the four segments of the transect. 
The number of broods observed decreased steadily on segments A to D as did the 
desirability of the habitat, 
Table VII shows water fluctuations on the different segments of the transect. 
General water rise on the southern end (segment D) was less than the northern end 
(segment A) because of less rainfall in that area. From north to south on the 
transect, the variation between the high and low water pauge readings was progress- 
ively greater on both the "B' and "C'' type potholes. This could be attributed to a 
combination of more rain on the northern end, the general land use, vegetative 
cover, pothole size and other factors. In any event, it shows that the potholes on 
the segments further north were more stable. Thus, the shore outlines were more 
stable and cover along the water's edge was more available for waterfowl use. In 
most instances the water on the areas in segment D had receded so that there was a 
strip of ground separating the water from the shore cover. Cover within the water 
was absent in the majority of the water areas there and in most of those that had 
cover, it was too thick to be attractive to ducks with broods, 
Table VIII is a summary of occupancy and of loss of water areas on the 
transect during the month of July and the beginning of August. It shows the greater 
loss of water areas toward the southern end of the transect in both coverages. It 
would be expected that as more of the water holes on the southern segments 'C" and 
"D'" dried up, a greater number of those remaining would be occupied by waterfowl 
that had moved in from the dry areas. This did not appear to be the case as the 
number of occupied areas also decreased greatly. This might substantiate the 
thought that the southern part of the transect is not the best of waterfowl habitat. 
