3 
is doubtful sinoe there is nothing to prevent a direct fll^it across any 
of the mountain passes* fhere is also a general migration southward* 
probably by a comparatively small number of birds, over the Booky Mountain 
Plateau, that carries the snowy herons and some of the dudes through the 
scattered lakes and ponds found in Utah, lew Mexico and Arizona. 
In examining these records it must be borne in mind that many of 
the birds banded at the mouth of Bear Biver in Utah were individuals that 
had not bred there* Drake pintails, and a few mallards begin to come into 
that region after the first week in June and continue to gather, perhaps 
from points far distant, from then until late 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* About lhanksgiving 
time the Bear Biver bays begin to freeze, and in normal years by December 
1, ducks are forced out of this region. An occasional open winter may 
permit their sojourn until January or later. A few birds 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 sheet distance northward into the Snake Biver drainage in Idaho. 
Banded birds were set at liberty near the Duck vilie dun Club at the 
mouth of Bear Diver save for & few that in It16 were given to the State Pish 
and dame Cotmission for exhibition at the Amaral State Pair in Salt lake Oily, 
and that were subsequentiy set at freedom near denova, Utah on the shore of 
Utah. lake. 
