MIGRATION RECORDS FROM WILD DUCKS AND OTHER BIRDS. 6 



Of the whole number banded, 994 were ducks, of which 174 were 

 recovered. The number of returns from birds of this group, a 

 little more than 17 per cent, indicates the results that may be 

 obtained from work in banding birds of this family. 



In considering these records it is to be borne in mind that 

 many of the birds banded at the mouth of Bear River, Utah, were 

 individuals that had not bred there. Drake pintails and a few 

 mallards begin to come in to that region after the first week in 

 June and continue to gather, perhaps from points far distant, from 

 then until late in fall. Migration out to other points begins about 

 the first week in September, and there is a constant shifting of the 

 waterfowl population during the fall as birds arrive from the 

 north or leave for other points. The Bear River bays begin to 

 freeze about Thanksgiving time, and in normal years by Decem- 

 ber 1 ducks are forced out of this region, although an occasional 

 open winter may permit their sojourn until in January or later. A 

 few remain to winter in Utah in sloughs or channels kept open by 

 spring water, but the majority perform extended flights to other 

 regions. Some of the wintering mallards pass a short distance 

 northward into the Snake River drainage in Idaho. 



Returns from all the records cover a vast area (see Fig. 1) extend- 

 ing from western Missouri and Kansas west to California, and from 

 southern Mexico (Guerrero) to Saskatchewan, Canada. A study of 

 the results indicates one general line of flight to the west from the 

 Salt Lake Valley to California, a route followed by green-winged 

 teals and shovelers and part of the mallards and pintails. Another 

 line of flight, taken by a group of birds that includes cinnamon teals, 

 redheads, pintails, and mallards, crosses to the Great Plains region 

 and thence south into Texas. Indications are that some of the birds 

 last mentioned fly nort^i and east to cross the divide separating Snake 

 River from the headwaters of the Missouri and follow down east of 

 the foothills of the Rocky Mountains; that all pursue such a route 

 is doubtful, since there is nothing to prevent a direct flight to the 

 east or southeast across any of the mountain passes. There is also 

 a third general migration southward over the Rocky Mountain Pla- 

 teau, probably by a comparatively small number of birds, that carries 

 the snowy herons and some of the ducks through the scattered lakes 

 and ponds found in central and southern Utah, New Mexico, and' 

 Arizona. 



MIGRATION AND OCCURRENCE RECORDS. 



Following is a list of species from which there have been no re- 

 turns, with figures to indicate the number of individuals banded and 

 set at liberty : Bandecl 



Western grebe : 4 



Pied-billed grebe 4 



California gull 1 



Ring-billed gull 1 



Baldpate, or American widgeon 14 



Ruddy duck 2 



American bittern 1 



Black-crowned night heron 7 



Avocet 6 



Black-necked stilt 4 



Marbled godwit 1 



