The assumption was made that in both cases the waters used for nesting and 
feeding were not adjacent to the nests, and in one case it was probably at a con- 
siderable distance. 
The data furnished by both diving ducks and river ducks indicate that the 
nesting site often bears no relation to the potholes used by the breeding birds 
for other activities nor to potholes used for brood rearing. 
Use of Water Areas by Flying Young 
Table 23 shows the dates on which young of the various species were first seen 
to fly and on which they were most abundant, and includes a very rough estimate of 
their abundance at this peak. 
Table 23. Dates of apvearance of flying young. 

Approximate 
Species First seen Peak number at 
peak 
Pintail 7/14 7/24 - 7/30 30 
Mallard : 7/14 8/1 - 8/20 60 
Blue-winged teal 7/23 8/21 - 8/29 1:0 
Canvasback 8/1 8/1, - 8/20 35 
Green-winged teal 8/8 8/21 - 8/29 9 
Shoveller | 6/1) 8/1 - 8/20 2 
Redhead | 8/14 8/1 - 8/20 2 
Baldpate | None seen flying 
Ruddy None seen flying 
Gadwall None seen flying 

These birds were extremely mobile and there was no possibility of determining 
the extent of their movements. They appeared to have no fixed base of operations 
and groups were rarely seen twice in the same place, The one exception was a group of 
29 young canvasbacks which occupied pothole No. 3 from August 1) to 20. There were 
only about six other flying young of this species seen elsewhere on the area. Oddly 
enough, this was the only pothole on which diving-duck hens were seen to gather. 
Eight canvasback and two redhead hens were seen repeatedly on this pothole from 
June 21 until July l. 
The following descriptive notes indicate the _types of areas preferred by those 
species for which there are any data. 
Pintail - Type Al areas: 1.5 acres or more in area, Found extensively in 
flooded fields after rain. 
Mallard - Type Al areas: 1.5 acres or more in area. Found extensively in 
flooded fields after rain. 
Blue-winged teal - Type Al areas: 1.5 or more acres, 
Canvasback ~ Only one area used, and that for only a few days. <A Type A3 area, 
3.5 feet deep and 3.1 acres. (The deepest pothole on the study areas.). 
Green-winged teal - Type Al areas of 1.5 acres or more. 
Birds of this age showed a definite preference for large, open potholes, 
