42 
water gauges, and in District 8, cover mapping. Later, the ''beat-out'' method was 
used to find broods. Most of the study areas were visited at least three times, some 
more often. (3) District 8, our best pothole country and the block used to test 
sampling methods was cross-checked by several.methods: (a) regular east-west 
aerial transects across the district at 12 mile intervals; (b) aerial transects flown 
repeatedly over ground transect routes; (c) ground transects re-worked several times 
by Kiel and assistants; (d) other ground transects covered twice by Conservation 
Officer Krentz; (e) special study areas amounting to 10 percent of the total areas along 
Kiel's regular transects; (f) ten quarter section blocks scattered throughout the district; 
(g) the 1 1/2 section Rosneath study block combed by a 12-man crew for breeding pairs, 
nests, and later for broods. (4) Whitewater Lake's total population was measured by 
flying strips across the long axis of the lake at mile intervals (giving 25 percent coverage), 
Species composition was obtained from the ground using an air-thrust boat. (5) Large 
marshes were sampled by canoe or aircraft flying strips, usually at one mile intervals, 
(6) Shore lines and channels were covered on a duck-per-mile basis. Some of the | 
methods employed are discussed in greater detail in the appendices. 
Weather and Water Conditions 
If abundant water were the only requirement of nesting waterfowl, ducks 
nesting in Manitoba would have had a "banner" year; they did not, however, in spite 
of the greatest spread of surface water in many years. 
A leading meteorologist attributed the super-abundance of water in Manitoba 
(and Western Ontario) this year to unusually heavy rainfall which saturated the soil 
before the freeze-up last fall, unusually deep penetration of frost, heavy late winter 
and early spring snow, sub-normal April and May temperatures reducing evaporation, 
and heavy spring rains with a quick run-off. Many weather and flood records were 
-broken during the course of these conditions. The net result on the waterfowl population 
was a two-week set-back in their entire migration and breeding chronology. 
Sub-normal temperatures continued throughout the nesting and brooding season. 
May was particularly cold and wet, possibly a factor in the poor hatch. From July 12 
to 15, when many broods were only a few days old, temperatures dipped almost to the 
freezing point, perhaps another factor affecting success. By the third week of August, 
a killing frost which caused considerable crop damage was recorded in Western 
Manitoba. For the period April 1 to August 14, which spans the nesting season, half 
of the crop reporting Districts in Manitoba listed a total precipitation figure 45-85 
percent above normal, the remainder showed 15-30 percent above normal. This and 
the cool weather helped maintain most potholes in good condition throughout the nesting 
season. 
Flooding has been a factor in reducing nesting success on several large marshes, 
including Netley and Delta, as well as in the area in western Manitoba which experienced 
a flash flood. On the favourable side, presumably, was the lateness of stubble plowing 
coupled with less than the usual amount of burning which should have reduced losses 
associated with farm operations of this type. 
The combination of cool weather and high water may be responsible for the 
sharp decline in disease mortality which in 1949 brought serious losses among moulting 
ducks in Manitoba. 
Population Statistics 
Manitoba's highest duck densities are found in three areas: (1) the farmlands; 
(2) the Saskatchewan Delta; and (3) the large marshes. This prime duck habitat is 
restricted to the southwestern and western third of the Province. The remaining two- 
thirds of the Province contains numerous water areas, supporting a widely scattered 
