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PACIFIC FLYWAY 
Summary of Pacific Flyway Winter Survey Data 
' By reason of the lack of data from wintering areas in Mexico, 
relatively little can be said regarding the trend in wintering populations 
throughout the flyway. However, on the basis of species which do not 
regularly move into Mexican wintering areas in significant numbers, 
the following comments can be made: 
Ducks 
Geese 
Brant 
- Based on wintering areas in the United States and north 
there would appear to have been a decrease in wintering ducks 
in the Pacific Flyway in 1957 as compared to the previous 
year. However, the decrease was mainly among pintail, bald- 
pate, green-winged teal, and shoveler, whichcollectively make 
up over 50 percent of the ducks in the flyway, and which 
regularly migrate into Mexico in rather large numbers. It is 
of interest to note that the mallard, which makes up about 
one-fifth of the total wintering population, remained unchanged. 
- The 1957 goose index is 25 percent below the average for 
the past eight years, and compared to individual years is: 
22. percent below 1956 
15 percent below 1955 
16 percent below 1954 
22 percent below 1953 
19 percent below 1952 
59 percent below 1951 
equal to 1950 
Among the geese, snows, cackling, and white-fronts 
were down, while Canadas were up slightly. 
- The 1957 brant index is one percent above the average 
for the past eight years and compared to individual years is: 
27 percent above 1956 
3 percent above 1955 
5 percent above 1954 
10 percent below 1953 
17 percent below 1952 
28 percent above 1951 
8 percent below 1950 
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