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on the northern end of the transect were up as much as half a foot above the May 1 
reading. The rains were not as heavy on the southern end of the transect but the 
potholes were up to or slightly higher than the May 1 levels. Good amounts of 
rainfall throughout June held water levels nearly constant. They gradually receded 
during July on the northern end of the transect but dropped much more rapidly on 
the southern areas. Growing conditions were favorable throughout July, however, 
some fields were so wet that such practices as 2-4-D spraying of broadleaf weeds, 
haying, and cultivating of fallow fields were difficult. 
Methods and Procedures 
Studies began in the area on May 5 when the transect was established. A 
number and a pothole survey form, to record all observations, were assigned to 
each water area on the transect. On the original survey, of potholes to be included 
in the transect, air photos were not available for all the segments. Those available 
were used to help locate potholes on the transect while the rest of the area was paced 
out to determine those areas to be included. Pothole type, immediate land use, and 
emergent vegetation were also recorded on the survey form. The transect was 
divided into four 10-mile segments which were lettered A, B, C, and D, from north 
to south. Air photos arrived later in the season and, with the help of these, graph 
maps of all included water areas were drawn to shape, size, and location. These 
graph maps, ona scale of 20 inches to the mile, were also used to record all land 
use, and type of grain crops on the entire transect. At the end of July, the principal 
species of aquatic vegetation, both submerged and emergent, were recorded on the 
survey forms. 
To maintain records of water fluctuations during the breeding season, 92 
temporary gauges were placed in roadside ponds of B, C, and E permanency early 
in May. These gauges were made of notched cedar lathe, Periodic readings were 
taken from the notch to the surface of the water. All gauges were placed near the 
road and on the south side of the selected potholes to make them easier to find later 
in the season after vegetation had grown enough to obscure them. Frost in the 
bottom of the ponds in early May prevented the erection of permanent gauges till 
later in the month. Nine of the temporary gauges were replaced by permanent gauges 
attached to 2" x 4" posts driven solidly into the bottom of semi-permanent potholes. 
The gauges were read bi-weekly and the readings recorded on the survey form. 
The first breeding pair count was begun on May 12 and was completed in 3 days. 
At that time, new growth had not appeared to hide the birds and the main cover was 
old cattail growth and water-killed stands of willow. The method employed on this 
count was to beat out any water areas where old vegetation hid any part of the pond. 
In the three additional breeding pair counts that were run at two-week intervals 
during May and June, the method used was the same as the first but the stands of 
new vegetation that appeared, made more thorough beat-outs necessary. 
During the intervals between the breeding pair counts, the main activities on 
the study area were mapping, gauge reading, re-checking active nests, and nest 
hunting. Most of the possible nesting cover in the vicinity of water areas was 
thoroughly checked for nests. This work was complicated by the abundance of nesting 
cover which in many instances extended as much as half a mile from a given pond. 
The largest part of the nest hunting was confined to segment A, the area of highest 
duck density. A dog was utilized for 2 days and it is our conclusion that one can be 
