44 
(c) Entire sets destroyed by seeding or disking. 
(d) Two mallards nests destroyed with young sitting on them; 
some, if not all, were killed. 
(e) Two hens injured on nests so that they had to be killed 
(1 pintail, 1 shoveler). 
Success of the Season 

The data for the July and August brood coverages are presented in Table II; 
the coverage of June 3-5 was primarily for pairs. Combining the broods seen in 
July with the Class I and II broods noted in August, a density of 23.5 per square 
mile is obtained. Combining the July broods, broody hens and potential later 
broods (indicated by pairs and lone drakes), this figure is 23,2, Pintails and 
mallards make up 15.1 of the broods per square mile (adjusted for unidentified) or 
64.3 percent. 
In 1948, Soper ran Transect No. 33 (cf. above) and No. 34 (Rosetown - 
Elrose - Glidden) sometime between June 16 and July 11. His data indicate 1,1 
broods per square mile for the former and 2.1 for the latter; he also records 
6.9 and 4.8 pairs per square mile, respectively, for totals of 8.0 and 6.9 broods 
per square mile. It is believed that these data are comparable and indicate about 
one-third of the 1952 production. 
With the appearance of the first broods, a difference between pintail and 
mallard nestings was indicated. Three pintail broods were noted on May 17, five 
days ahead of the first mallard brood. The June 3-5 coverage showed 25 percent 
of 121] pintail broods to be a week, or less, old while 65 percent of the 34 mallard 
broods were in this category. Both species reportedly arrived back at the same 
time and their incubation periods are similar. Apparently pintails settled down to 
nesting a few days earlier than mallards. Normally this might not mean much but 
this year, with such widespread spring harvesting, it apparently made the difference 
between little and moderately heavy re-nesting. The July coverage showed 39 percent 
of 101 mallard broods to be in the downy stage, while only 9 percent of 202 pintail 
broods were in this class. On the same coverage, 80 percent of the pintail broods 
were Class III compared to 32 percent of the mallards. While differences in the 
length of the pre-flight period might account for some of the Class III percentages, 
the more even distribution of mallard broods in all age classes probably reflects 
re-nesting attempts due to agricutlural losses. This, however, does not mean 
that pintails were more successful on the whole than mallards, A comparison of 
broods to pairs (Table II) shows that pintails were 36 percent successful while 
mallards were 41 percent. This means that 2.8 pairs of pintails produced one brood 
while only 2.5 pairs of mallards did the same. This is a further indication of the 
pintail's earlier nesting; it suggests that agricultural losses suffered by this species 
were actually much heavier than those suffered by the mallard, but many of the pintail 
hens did not renest because the losses came at a much later stage in incubation. 
Because of the nature of the study area, there is some doubt that the brood-to- 
pair comparison is valid. In May only one area in five was partly beyond the transect 
line; in August this ratio was one to one. In general, this meant that the majority of 
pairs registered in the transect took their broods to areas partly in and partly out of it. 
