WILD DUCKS OF THE BEAR RIVER MARSHES, UTAH. 9 
FALL MIGRATION. 
The number of wild ducks on the Bear River marshes continues to 
grow until about the 1st of September; during the latter part of 
August the increase is rapid, as hordes of young ducks that have 
been reared on the uplands and along small streams and lakes in the 
mountain valleys begin to arrive. Between the 1st and the 10th of 
September there is a sudden diminution in the numbers, and at this 
time fully two-thirds of the ducks leave the marsh and migrate to 
other regions, apparently far distant. The great mass of cinnamon 
teals and redheads leave the marsh then and with them go many 
pintails and others. The sudden disappearance of numbers of the 
ducks is noticeable, and can not fail to attract the attention of one 
closely in touch with the daily course of the wild life on the marsh. 
The exodus seems to take place at night, and bays and lagoons that 
one day are banked solidly with rank after rank of resting waterfowl 
may 2-± hours later show individuals only in tens where before they 
were represented in hundreds. That this migration is to distant 
points seems certain. A drake pintail that had been banded and 
released at a field laboratory near the Duckville Gun Club on these 
marshes September 4, 1916, was killed 11 days later not far from 
Glasgow, Mont. 
Ducks again begin to gather on the flats, however, and by the 
opening of the hunting season enormous numbers are once more 
present. These are composed of young birds and adults that have 
come in from other regions, of young from late-hatched broods on 
these marshes, and of adults that after completing the molt have 
come out from the seclusion of the rushes. There is considerable 
movement night and morning among these birds, but they have no 
such regularly established lines of flight at this time as they do after 
two or three days of shooting. From October 8 to 15 many addi- 
tional ducks come in from the north, their arrival depending upon 
cold storms that drive them from more northern localities. From this 
time on the migration from the north is steady. Several species ar- 
rive that are rare or absent during the breeding season and so add 
to the duck population of the marsh. The canvas-back is fairly com- 
mon after October 10, while the snow goose, buffle-head, and golden- 
eye, or whistler, are present in some numbers after October 15. 
Lesser scaup ducks, or bluebills, come at about the same time, but 
are not common until a week later. Besides these a few other species 
appear in very small numbers. The ducks are said to remain 
in fall as long as there is open water in the channels or bays, but 
most of them are reported to leave finally between December 1 and 
15. The date of departure varies with the year and may be earlier 
or later, according to the season. 
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