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 24 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 clucks 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-heacl, 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. 

 20862°— 21 2 



