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slightly by late-hatched ruddy, redhead, and blue-winged teal broods appearing after 
the brood survey was made, However, such late broods of ruddies and redheads, 
some in Class 1 on September 1, will not reach flying stage before the hunting season 
opens. The greatest decline appears in the puddle-duck species. It is probable that 
repeated heavy rains combined with a late, cold apning caused the poor success of 
land-nesting species, : 
Re-checks of transects after the original brood survey revealed that, by 
August 4, 48 percent of the broods were in Class 111. Average brood size was 
approximately the same in District 8 for 1949 and 1950. 
Water levels measured with gauges in the 120 special-study potholes were 
higher than in 1949. Levels were high in early spring and remained so with little 
fluctuation during the summer over most of the district. There was no apparent 
indication that high water levels made diving-duck nesting habitat less desirable in 
the potholes. New growth of aquatics was especially dense. 
In addition to furnishing water level data, special-study potholes were the 
source of data on vegetation changes in ae potholes and land-use practices around 
them. 
Nest and brood data gathered in District 8 are included in the Manitoba 
report. 
Summary 
A second-year study of waterfowl productivity in Manitoba Inventory District 
8 revealed that a 15-17 percent increase in the breeding population did not result ina 
corresponding increase in production. Instead, a 34 percent decrease in number of 
broods was indicated by July brood surveys comparable for 1949 and 1950. Late- 
hatched broods offset this decrease only slightly. Apparently, repeated heavy rains 
combined with a late, cold spring caused the poor production. 
Water levels in April 1950, were higher than in April 1949, and remained 
higher throughout the summer over most of the district. 
Methods being used to measure waterfowl breeding populations and production 
in District 8 included ground transects, special-study potholes, aerial transects, and 
quarter~section study blocks. 
