OT ae a ee oe we eel 
SCOPE OF INVESTIGATIONS AND METHODS USED 
Winter Survey 
During recent years the survey of waterfowl wintering grounds 
has included the major wintering areas in Alaska, Canada, the United 
States, and Mexico. In January 1957, due to circumstances beyond our 
control, it was not possible to carry out the survey in Mexico. In view 
of the fact that there has been a considerable shift in the winter distri- 
bution of birds between wintering areas in Mexico and the United States, 
it is necessary that information be available from both countries before 
the data are meaningful. For example, without data from Mexico any 
change in the numbers of several species of ducks observed in the 
United States might not indicate a change in population size, since more 
or less birds could have migrated into Mexico. The 1957 winter survey 
figures for the Pacific and Central Flyways are questionable for this 
reason. 
In the United States, the Bureau of Sport Fisheries and 
Wildlife organized the surveys but the bulk of the field work was carried 
out by personnel of the 48 State conservation agencies. In Alaska the 
survey was carried out by Bureau personnel, while in Canada ‘the 
Canadian Wildlife Service organized the survey and the field work was 
conducted by the Canadian Wildlife Service and the Provinces. 
The wintering areas were surveyed by means of observers in 
boats, cars, and aircraft with all important areas being covered from 
the air. Available information as to personnel, equipment and distances 
traveled is presented in the following table. 

| No. Observers Aerial Observation Miles Boat 
Location U.S. State Other No.,Planes Mi.Flown Driven Hr. 
Pacific Flyway 53 310 Z 32 18, 265 9,700 30 
Central Flyway 66 331 25 38 23,220 44,740 44 
Mississippi Flyway 71 771 62 44 23,920 46,950 54 
Atlantic Flyway 46 201 6 36 20,210 8,260 34 
Total | 236 1,613. 95 -150.- .- 85,615 109,650 162 

