
Winter Trend Data - Central Flyway 
Yeather conditions during the survey period varied from 
satisfactory to excellent. Tog, low ceilings, and poor visibility 
were experienced in limited areas but none of these conditions 
materially interfered with the survey. Generally, the coverage 
throughout the Flyvay was comparable to that of previous surveys. 
Based on comparable coverage between 1953 and 1959 there 
were marked decreases in the wintering populations of mallards, 
scaup, gadwall, shoveller, and canvasback. Moderate to considerable 
increases were recorded for pintail, redhead, green-winged teal, and 
blue-winged teal. 
Among the geese, the populations of snow and blue geese 
decreased considerably, white-fronted goose populations continued to 
decline, and Canada goose populations remained about stable. 
Coot population indices decreased moderately. 
At this point it seems appropriate to comment on an 
apparent discrepancy between population trends of some species as 
portrayed by the annual winter survey and the population data 
recorded during breeding ground surveys. For example, the redhead 
breeding population index reached a peak in 1956. Between 1956 and 
1958, the index decreased approximately 40 percent. Between 1958 
and 1959, the total breeding population index did not change materi- 
ally although there was a further exodus of birds out of the 
important redhead breeding areas in southern Alberta and southern 
Saskatchewan. Between 1956 and 1958 the winter index decreased 47 
percent, which agrees quite well with the 40 percent decrease 
recorded on the breeding ground. Between 1958 and 1959, however, 
the total redhead wintering ground index increased 5 percent. 
Since drought conditions in 1958 adversely affected redhead 
breeding habitat, and since the 1958 season started off with a much 
reduced redhead breeding population, it is doubtful that an increase 
of 54 percent could have occurred. Since the bulk of the wintering 
redhead are recorded annually in the Central Flyway it does not seem 
that the 72 percent increase recorded in this Flyway between 1958 
and 1959 properly reflects the population trend. 
In addition to the redhead, there are differences in the 
population trends of some other species as measured by the breeding 
population and wintering ground surveys. At the present time we do 
not have an explanation for these discrepancies. 
