43 
Breeding Population Trends 
Work on the area was started much too late to obtain a clear picture of the 
progress of the breeding cycle. The data from the coverages made for breeding 
pairs are presented in Table I; species composition are to be found in Table II. 
The average density of these four coverages is 58.8 pairs per square mile with 
pintails and mallards accounting for 40 of these. Soper (Special Scientific Report 
No. 60) in 1948 reported 11.7 pairs (including lone drakes) per square mile on his 
May 11 - June 10 coverage of transect 33 (Kerrobert to Kindersley to Rosetown); 
his ducks -per-square-mile figure is 24.5, Whether or not these figures are 
directly comparable with 1952 is not known. 
On the first coverage over 80 percent of the pintails and mallards seen were 
drakes, indicating that the season was well advanced; this was verified by the 
appearance of three broods before this first round was completed. It is known that 
figures for the first coverage are high because some birds beyond the transect line 
were not marked so that they could later be segregated. The variations in the 
numbers of mallard and pintail pairs probably were due primarily to the movements 
of flocks of drakes (each individual taken to represent a pair) in and out of the 
transect. While the samples are small, there are indications of an influx of 
shovelers, green-winged teal and gadwall into the area the last week of May, and 
of blue-winged teal the first week in June. With the small number of divers, their 
location on the larger water areas could easily account for the population fluctuations. 
Nesting: An attempt was made to locate nests by car and on foot and follow them to 
completion, but only 85 were found and the outcome of many of these could not be 
definitely determined because of the difficulty of marking them permanently on land 
undergoing cultivation. Pintails and mallards apparently made most use of the 
swath and stubble, but gadwall, green-winged and blue-winged teal and shovelers 
were also found nesting there. The heaviest nesting density found was on June 5 in 
a 160-acre stubble field containing a six or seven acre slough. By driving a car 
ten miles through the field, effective coverage was given to about three acres; the 
density for this sample was four nests per acre; twenty-two nests of the above named 
Species were actually found although the field was not thoroughly covered. It was 
being seeded that day and, in all probability every nest was partially or wholly 
destroyed. 
Predators were apparently few. Richardson's ground squirrel, while fewer 
than in the past few years, was the only rodent seen in numbers sufficient to cause 
damage. One coyote was seen, one family of skunks and no badgers, although they 
were present. Magpies were very scarce and crows were sparsely distributed; the 
only trees are in windbreaks around farms. 
Losses attributable to agriculture were seen to take on several forms: 
(a) Two cases of pintails incubating 100-150 yards from the road, 
but in plain view from it, all nesting cover having disappeared 
in harvest operations. 
(b) Several instances of birds incubating 3-5 eggs (sometimes 
l or 2 cracked) with several broken eggs nearby. 
