; noticed at 2:00 P.M. By late afternoon the vanguards 

 ' had reached southern Minnesota and northwestern Iowa. 



Shortly after sunrise on November 2, the vanguards 

 of migrating waterfowl reached Reelfoot Lake, Tennes- 

 see, and northern Arkansas. Later in the day, they 

 showed up in northern Louisiana. The rear echelon of 

 migrating waterfowl, which left southern Canada on 

 November 1, reached Louisiana on November 3. 



It is between 1,400 and 2,000 miles from various 

 waterfowl marshes in southern Saskatchewan and 

 Manitoba to southern Louisiana. Many thousands of 

 ducks made this flight in 2 days. At an average speed 

 of 40 miles per hour, these waterfowl would have flown 

 this distance in 35 to 50 hours. It appears likely that 

 some waterfowl made this flight without stopping. 



While large numbers flew during the night, other 

 waterfowl alighted on lakes and marshes to spend the 

 night and resume migration the following day. The 

 flight schedule is illustrated by population changes at 

 Crane Lake, Bath, Illinois, where numbers rose from 

 65,000 in the morning to 120,000 by evening of Novem- 

 ber 2 and declined to 85,000 by the morning of Novem- 

 ber 3, and by Sieh's observations of mallards which 

 alighted on Big Spirit Lake, Iowa, the afternoon and 

 night of November 1 and took flight periodically through- 

 out the morning of November 2. 



Altitude of Flight." Under fair weather conditions, 

 waterfowl may fly so high as to be invisible, or almost 

 so, to the naked eye. In aviating over Illinois, we have 

 found ducks at maximum altitudes of 3,000 to 4,000 

 feet. Under storm conditions, or over large rivers, 

 waterfowl commonly fly at much lower altitudes. 



The storm conditions which prevailed at the time 

 of the November 1 and 2 waterfowl migration resulted in 

 the birds flying so low as to be readily visible from the 

 ground. In North Dakota they were observed flying at 

 200 to 300 feet, so low that many of them were shot. In 

 Minnesota, the highest ducks observed from a plane 

 were at 800 feet, the lowest at 100-150 feet. Observers 

 near several Iowa rivers estimated that flocks of ducks 

 were flying at 100 to 800 feet. Over the state of Mis- 

 souri, large numbers of migrating waterfowl were only 

 100 feet above the ground. Over the Mississippi River 

 valley in Illinois, flocks of ducks were stacked at ele- 

 vations of 200 to 2,000 feet. For a distance up to 40 

 miles west of the Mississippi River in southern Mis- 

 souri, mallard flocks were at altitudes that ranged be- 

 tween 400 and 1,000 feet. Observers in a plane over 

 northern Arkansas saw mallards flying at 1,500 feet. 



SPECIES IN FLIGHT 



Probably all species of ducks common in the 

 Mississippi Flyway, with the exception of the blue- 



winged teal, were involved in the mass migration of 

 October 31 and November 1 and 2, 1955. However, all 

 observers concurred that the flight was predominated by 

 the mallard, followed in numbers by the lesser scaup. 

 Other species which appeared to be important com- 

 ponents of the flight were the gadwall, pintail, green- 

 winged teal, widgeon, and canvasback. 



EFFECT OF WEATHER ON FLIGHT 



The mass waterfowl migration emanating from 

 southern Alberta and Saskatchewan on October 31 and 

 southern Manitoba on November 1, 1955, was undoubt- 

 edly influenced by several components of weather. 

 Which was the most important in triggering the migration 

 is difficult to determine. 



Barometric Pressure. —Weather conditions in Al- 

 berta, Saskatchewan, and Manitoba on October 31 and 

 November 1, 1955, were associated with two low pres- 

 sure areas. One low pressure area moved across the 

 Great Plains from Alberta to Manitoba. The other low 

 pressure area moved from Wisconsin to Churchill, Mani- 

 toba, where it deepened to influence weather conditions 

 over much of the continent. 



In a recent book on waterfowl, Hochbaum (1955:106- 

 7, 137) stated that ducks select anticyclonic (high 

 pressure) weather for the start of their mass migrations. 

 He cited a specific observation on October 30, 1954, 

 and "many similar observations" as evidence that high 

 pressure, with its attendant clear sky and favorable 

 wind, is a prerequisite for the beginning of mass mi- 

 gration. Certainly the migration which took place during 

 the period October 31-November 3, 1955, the largest 

 waterfowl movement in the Mississippi Flyway since 

 November 11, 1940, was not begun under these con- 

 ditions. Neither was the famous waterfowl migration on 

 November 11, 1940, which was initiated by weather con- 

 ditions associated with a deep low; the low moved 

 rapidly into the Mississippi River valley from the south- 

 west, creating the "Armistice Day storm" which made 

 history. 



Wind." Recent studies of small birds strongly sug- 

 gest that wind direction is an important factor in the 

 initiation of their migration. 



Devlin (1954:93) correlated wind direction with 

 autumnal, nocturnal migration and concluded that birds 

 were in flight on nights with light to moderate north or 

 northwest winds. After studying bird migration in 

 Lincoln Park, Chicago, Bennett (1952:219) concluded 

 that "The autumn migration waves are associated with 

 cold fronts followed by strong NW to N winds." 



Dennis (1954:111) concluded after observing the 

 spring migration of birds in Texas that "Southerly 

 winds, rising temperature, and falling barometric pres- 



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