SUMMARY OF SEASONS AND MIGRATIONS 
Waterfowl timetables 
Normally, by the time the hunting season opens on the Upper 
Mississippi Refuge, most species of ducks which use the area are 
already present, although not always in large numbers. By mid- 
August, populations start to build up, with blue-winged teal, 
American widgeon, and wood ducks being the first to start moving. 
By the end of the first week in October, the first cold snap of 
the fall has usually already occurred, and most of the blue-wings 
and a large part of the wood ducks have moved out of the upper 
portions of the Upper Mississippi Refuge. By mid-October, these 
two species are normally gone from the upper half of the refuge. 
In 1953 the Branch of Refuges adopted the system of record- 
ing waterfowl use in terms of duck-days use, a figure derived by 
multiplying the average weekly populations by 7. This gives 
some measure of the overall use of an area, and provides a better 
basis for making comparisons from year to year. 
Table 3 indicates an effort to convert previous waterfowl 
use data to duck-day use so that for the entire period of this 
study some comparison might be available. In this table, duck- 
day use before the fall of 1953 has been computed from data 
available in the files, while from 1953 through 1960 the weekly 
census figures were regularly converted to duck=day use. 
Table 3 = Comparative Duck Day Use (Upper Mississippi Refuge) 
Computed from old data Compiled under new system 
Year Duck days use Year Duck days use 
1946 13 ,651 ,880 1953 8 ,842 ,540 
194-7 10 ,238 ,910 1954 9 ,235 ,149 
198 12 ,286 , 700 1955 10 ,560 ,9k9 
1949 14,744 ,050 1956 11,489 ,961 
1950 15 ,333 ,820 1957 14 ,298 , 774 
1951 T ,666 ,910 1958 12,851,426 
1952 6 ,900 ,220 1959 8 538,215 
1960 11,215 ,645 
As shown in tables 5 through 8, there has been a wide spread 
in the time of peak population build-ups in the area under study. 
On the Upper Mississippi Refuge, the earliest peak recorded 
occurred during the week ending October 11, 1958, while the latest 
peak occurred during the week ending November 28, 1953. On the 
average, the peak of the flight normally takes place about the 
first week in November. 
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