85 
Method Date Time Wind (mph) No. Broods 
Aerial 7/17 11:00 am 15-20 6 
to 4:30 pm 
Ground beat-out 7/ 5 to Throughout the day - 93 
7/23 Weather variable. 
Pilot Noltemeier made the aerial observations. Since only study potholes were 
observed -- and I pointed these out some distance ahead of the aircraft -- the aerial 
observer could concentrate on these potholes. This is an advantage for aerial obser- 
vation not found in most transect flying in this area where pothole densities are 
commonly 80 per square mile. Wind of 15 to 20 miles per hour at this time of day is 
very common on the Prairie during this survey season, and brood transects are 
regularly flown under these weather conditions, 
Air-ground comparisons are not available for this district to show whether or 
not the countability of broods varies importantly from year to year under changing 
habitat conditions, These 1953 data do indicate, however roughly, that there is a 
difference between aerial countability of broods in open-type potholes and potholes 
representing the district as a whole. 
Summary 
Trends in the waterfowl breeding population and production were studies ina 
4,000 square mile district in southwestern Manitoba. 
The duck breeding population remained at almost the same density and species 
composition as in 1952. Brood production, as measured on 120 study potholes and 
by road-counts, declined 11 percent and 19 percent, respectively. However, late 
broods probably brought production up to the 1952 level. 
Phenologically, 1953 was 7 to 10 days later than 1952. 
Air-ground comparisons indicated that time of day and type of habitat affected 
the countability of broods from the air. 
