
58 
Further analysis of pintail and mallard duckling mortality by compar - 
ing average hatch per successful nest with averape cambined Classes IIc and II 
brood size indicated mortalities of 39.3 and 24.4 percent respectively (Table VII.). 
It appears that although the pintail is the more successful nester, it is less success- 
ful than the mallard in rearing young to the flying stage. These figures supgest 
that the most perilous period for ducklings is the first day or so after hatchings. 
Production 
Estimated production of ducklings attaining flight was made by applying ¢ 
the corrected brood production figure of 266 to the average brood size of 6.48 for 
all species. This resulted ina total of 1.724 flying young, or 154.3 per square 
mile, ' 
However, we consider these to be minimum production figures since 
it was felt that a sizeable but unknown number of broods were missed during the 
second and third beat-out counts when all water areas were choked with dense 
stands of emergent aquatics. The likelihood of flushing broods out of the water 
area and overland when we entered the pothole from the distant end must also be 
considered. To further illustrate, a comparison of the first nesting attempt 
success was made with the percent of females accompanied by young (Table VIII.). 
Although our nesting studies indicated a high 64.9 percent successful hatch for 
pintail first attempts, the brood surveys indicated thatonly 32.5 percent of the 
females were with broods. The mallard exhibited a 61.8 percent successful first 
nesting attempt as compared to 29.5 percent of the breeding females being with 
broods. Itis unknown how much of these discrepancies are due to unrepresentative 
sampling of nesting habitat, or to our failure to locate all broods. Each of these 
phases must be further investigated. 
Banding 
A total of 513 ducks of eight species were banded on the Success Study 
Area during the summer (Table I[X.), 
r 
Table I, - Monthly Precipitation During 1955 as Compared to the 1922-1954 
Average. 
Precipitation in Inches * 
Year Jan. Feb. Mar. Apr. May June July Aug. Total to Aug. 
1922-1954 0.71 0,52 0.65 0.84 1,62 2,92 1,90 1,79 9.16 
1955 0.82 0.41 1.29 2.15 2.65 1.67 4.06 - 13.05 
% Difference +15 -21 +498 +151 +64 -43 +114 - +42 
* From records of Dominion Experimental Farm, Swift Current, Saskatchewan. 
