Table 2. —The change in waterfowl populations in 

 Martin County, Minnesota, as a result of migration on 

 November 1, 1955.* 



Table 4. —The change in waterfowl populations in 

 Louisiana as a result of migration on November 2 and 

 3, 1955.* 



Illinois, as a result of migration on November 2, 1955. 



Number of Ducks Observed 



had risen to 663,000, about the same number as were 

 present on November 2, 1954. By November 3, 1955, the 

 calculated duck population in the area had risen to 

 1,487,000, whereas on November 2-3, 1954 (2-day 

 census), it was about 693,000. Not until November 14 

 did the 1954 duck population rise to a peak comparable 

 to that found on November 3, 1955. It thus appears that 

 weather conditions prevalent on October 31 and Novem- 

 ber 1 and 2, were responsible for accelerating the mi- 

 gration by almost 2 weeks in 1955. 



*Data providefi by Richard K. Yancey, Louisiana Wild 

 Life and Fisheries Commission. 



DAILY WEATHER CONDITIONS 



The following review of weather conditions leading 

 up to and during the mass migration of waterfowl on 

 October 31 and November 1-3, 1955, was made from 

 weather maps of the United States Weather Bureau and 

 the Meteorological Division of the Canadian Department 

 of Transport. These maps, temperature records, and 

 comments on weather conditions reported by field men 

 of Ducks Unlimited of Canada provided useful means 

 for analyzing the relationship between weather con- 

 ditions and the mass migration. 



October 29."The weather map for 6:30 P.M.. 

 C.S.T., showed a fairly deep low pressure area centered 

 over northeastern Wisconsin. From the low, an east- 

 ward-moving cold front extended in a semicircle through 

 western New York, central South Carolina, and north- 

 central Florida. Also from the low. a westward-moving 

 warm front extended northward across James Bay. High 

 pressure areas occurred over Churchill, Manitoba, and 

 the District of Mackenzie. 



October 30."By 6:30 P.M., C.S.T.. the cold front 

 had become stationary and extended from Quebec east- 

 ward to the coast of New Jersey; the warm front had 

 moved from its October 29 position a short distance 

 northwest to Hudson Bay. The low pressure area that 

 had been centered over northeastern Wisconsin on 



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