by future data collecting and analysis. Possibilities that can 
be foreseen include modifications of area boundaries according 
to average seasonal phenology (which does not proceed evenly from 
south to north), delineation of most consistent areas from the 
phenological standpoint, and modification of the mechanics of 
evaluating waterfowl groups and numbers observed. 
As our knowledge of the distribution of breeding black ducks 
increases, accuracy in measuring fche size of the black duck breeding 
population can be improved in a number of ways. The boundaries of 
the breeding range to be surveyed can be better defined. In this 
regard, exploratory transects have been flown adjacent to the area 
regularly surveyed and data have been gathered from west of James 
Bay and in the New York - New England area. Some areas still to 
be considered include the coast of Labrador, Newfoundland, Nova 
Scotia, and northern Michigan. Since the harvest potential of the 
various black duck breeding populations is of major concern to those 
responsible for the management of the resource, this factor must be 
considered in the final decisions on what populations shall be 
permanently included in the survey area. 
Analysis of data collected to date has not led to a useful 
stratification of the black duck breeding range based upon differ¬ 
ences in density of breeding birds. A stratification based upon 
differences in phenology offers promise in helping to reduce a 
bias. In this connection, the possibility that coastal areas should 
be sampled as a separate stratum will be examined. 
Determining the annual status of the black duck breeding pop¬ 
ulation on a continental basis is an immediate management goal; 
however, the status of subunits within the total population also 
has important management significance. As techniques improve, this 
further refinement should be viewed as a long-range goal. 
There are a number of objectives of aerial surveys of water- 
fowl in eastern Canada which have not been discussed in detail in 
this report. One of these, the production survey conducted in 
July, attempts to measure waterfowl production. Recently, special 
effort has been made to band samples of immature and adult black 
ducks before the hunting season in Canada and the Northeastern United 
States. If this effort is successful in obtaining representative 
samples of the pre-hunting-season black duck population, useful 
information can be derived from the band recoveries. When banding 
data are combined with data from the Bureau's annual wing collection 
survey, an estimate of the age composition of the pre-hunting-season 
black duck population can be made. Age composition data, taken over 
a period of years, provide an indicator of annual production and 
show whether production is variable or uniform from year to year. 
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