92 

Summary 
Waterfowl population and production studies were continued in 1955 
over 59 square miles of prairie marsh in south-central Manitoba. 
Water level increases of one and one half feet over the fall of 1954 
resulted in the extension of the marsh southward and vegetational changes that 
increased the usefulness of the marsh to molting waterfowl. 
Concentrations of pintail, baldpate and mallard were apparently 
responsible for the increased post-breeding populations of 1955 when compared 
with those of 1953 and 1954, 
An extended nesting season and late hatch (particularly among the 
diving ducks) provided a final production figure !net was apparently somewhat 
higher than that of 1954. 
