POPULATION AND PRODUCTION TRENDS ON THE DELTA MARSHES OF 
SOUTH-CENTRAL MANITOBA, 1954 
S. T. Dillon 
Introduction 
Aerial estimates of the Delta Marsh waterfowl population have been made. 
since 1947, primarily by U.S. Fish and Wildlife Service and Delta Research Station 
personnel. It has been only during the past two years that attempts have been made 
to estimate this population at regular intervals. 
Methods 
An aerial survey system consisting of a set of seven, east-west transects, 
falling along section lines and covering that portion of the Delta Marsh from 
Clandeboye Bay to the Delta road was established. These transects total 44 linear 
miles. A strip one-eighth mile on each side of the aircraft was considered the zone 
of observation thus providing a 25 percent sample of approximately 44 square miles 
of marsh. When only one person is observing the sample size is reduced to 12.5 
percent. This survey system is essentially like that initiated in 1948 by A. S. Hawkins 
and D. L. Spencer of the U.S. Fish and Wildlife Service. 
In 1953 I flew entirely with U.S. Fish and Wildlife Service or Manitoba 
Government Air Service personnel. This year, to maintain regularity of observation, 
I relied upon rental aircraft supplied by the Portage Flying Club of Portage La Prairie, 
Manitoba. In addition I made two flights with Charles Evans (Fish and Wildlife Service) 
and two flights with the Manitoba Government Air Service. Information from another 
MGAS flight was made available to me by J. L. Howard and Nolan Perret of the 
Manitoba Game Branch, 
A dictaphone was used to record species and numbers of waterfowl seen on 
all flights with the U.S. Fish and Wildlife Service. Otherwise I employed a system 
of hand tally. 
Marsh-level counts were made on two occasions (July 26 to July 30, 1954 
and August 5 to August 11, 1954) using a freighter canoe powered by a Johnson, 
5 h.p. outboard motor. Either George Shand or Ralph Hancock of the Manitoba 
Game Branch operated the motor while I kept records. A system of 19 shoreline 
transects established by the Manitoba Game Branch constituted the survey. These 
transects cover an estimated 35 miles of shoreline which represents a 16 percent 
sample of the total shoreline. I cannot vouch for these two Statistics as I do not know 
how they were obtained. 
