
- during the hunting season on the Upper Mississippi Refuge amounts 
to 111,700 ducks, while for the entire area the average weekly 
population during the open season is 420,150 ducks. Thus it can 
be seen that duck populations during the period of hunting are 
high enough to provide a good supply of birds for the hunters. 
These data are shown in tables 10 through 14. 
Species composition of the flight 
Over the entire area, mallards account for 72.40% of the total 
duck flight. On the Upper Mississippi Refuge, there is a more 
balanced composition, with mallards accounting for only 37.60% 
of the total flight, while widgeons follow with 14.58% and scaup 
come third with 12.88%. Wood ducks represent 4.13% of total fall 
populations on the Upper Mississippi Refuge alone, but only 1.744 
on the combined areas. 
Table 15 shows that while mallards account for only 37.60% 
of total use on the Upper Mississippi, they account for almost 
all of the use on Mark Twain. This difference is believed due to 
a southeasterly movement of mallards which reach the Mississippi 
River. In some years this is a late season movement, accounting 
for peak populations on Batchtown and Calhoun Refuges late in 
December. Species composition of the fall flight is shown in 
table 15. 
Mass migrations 
One of the best-known mass migretions of waterfowl occurred 
prior to the period of this study. This movement took place dur- 
ing the Armistice Day (November 11) storm of 1940. Comparatively 
few ducks were present on the refuge prior to that storm. Armi- 
stice Day dawned bright and sunny, with little indication that by 
mid-day there would be an abrupt change in the weather. By noon, 
ducks started moving down the valley by the thousands, riding 
ahead of a storm front that pushed almost all the ducks before it; 
and by the next day when the storm had subsided most of the water- 
fowl had moved south. Never in the memory of hunters in this 
vicinity had so many ducks moved through in so short a time. 
Mass migrations were observed in 4 of the 15 years involved 
in this study. Those years were 1947, with a heavy flight on 
November 6 - 10; 1948, with two good movements on November 6 - 7 
and December 3 - 8; 1955, when on November 1 - 3 one of the 
heaviest flights in years occurred; and 1956, when a mass flight 
took place on November 7 - 9, but not comparable to the 1955 
movement. In 1959, an early freeze pushed most ducks out of the 
Upper Mississippi Refuge between November 14 and 21, but the over- 
all picture remained unchanged because of a late-season build-up 
of mallards on Mark Twain. 
