
During the other 10 years there was a steady dribble of 
birds through the valley, leading to a build-up in populations. 
Even in those years, several periods of good flights occurred, 
but not in the nature of "mass migrations" of 1947, 1948, 1955, 
or 1956. The following chart very briefly summarizes the move- 
ments each fall: 
Year Major Flight 
1940 Armistice Day flight was heaviest on record. 
1946 Heavy flight recorded November 6-10. 
1947 Two periods of heavy flight: November 6-7 and December 3-8. 
1948 Steady movement through, with no heavy migrations. 
1949 Steady movement, with no heavy migration. 
1950 "Bluebird weather," with no mass flight; best movement on 
November 7-10. 
1951 Steady dribble; best movements on October 7, 18, 31, and 
November 4. 
1952 Steady movement, but two "peaks" - October 19-25 and during 
blizzard of November 9-15. 
1953 Steady flight; 92% increase in duck day use over 1952. 
1954 Steady flight, with three fair movements: November 1, 
November 23-27, and December 5. 
1955 Mass movement on November 2 was the heaviest Single flight 
since Armistice Day, 1940. 
1956 Heavy movement November 7-9, but not comparable to 1955. 
1957 Steady flight. Best October 26 and November 2, and the peak 
on November 9. Drop of 40.9% in mallard numbers below 1956. 
1958 Steady dribble; heavy movement out of Upper Mississippi in 
mid-November; late mallard build-up on Mark Twain. 
1959 Steady dribble. Best movement in late October and November 
4-5. Mallards down 41.84 below 1958. 
1960 Steady flight. Good movement in late October and December 3. 
Mallards again down 23% below 1959. 3 
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