8 BULLETIN" 936, U. S. DEPARTXEEXT OF AGRICULTURE. 
end of South Bay, and a week later there were many hundreds. 
Birds that were shot for examination had the genital organs greatly 
enlarged, showing that they had finished breeding recently. They 
began molting into the eclipse plumage at once, and the mud flats 
where they rested during the day were strewn with cast-off feathers. 
In 1916 pintails appeared even earlier in the season; on June 7 
about 100 drakes were found in South Bay, while on the following 
day their numbers had been augmented to approximately 1,000. 
On June 14 a flock of male pintails in the region known as Lands 
End was estimated to contain between 2,500 and 3,000 birds. With 
these were only two or three females. As it was estimated that in 
1916 there were only 130 pairs of breeding pintails in this entire 
marsh area, it will be seen that there was a great influx of males at 
this time. T\ T here these summering birds nest is of course uncertain, 
but they must gather here from great areas that apparently lie 
largely outside of Utah. Though the pintails arrive first, they are 
soon joined by many mallards and shovelers, of which, a part come 
from the surrounding marsh and a part from other regions. These 
males steadily increase in number and, joined later by broods of 
immature birds, form great banks of ducks that rest during the day 
on the shallows covering the mud flats. 
The Canada geese follow a different procedure in their molt. They 
nest early, and as soon as their young are strong enough they take 
them far down on the fiats. The adult birds are more or less in 
evidence until about May 25, when most of them disappear. At this 
season adults and young frequent the great growths of rushes 
(Scirpus paludosus) in the lower marsh, and while hidden here the 
adults molt their flight feathers. In 1916 a number of families of 
geese lived in the lower part of Hansens Island through this period 
of molt. In feeding they apparently ranged over considerable areas 
and at night came into dense green rush growths near the open bays, 
where they slept close together on small hummocks. At this season 
they were warier than ever and seldom was one seen. In the heavy 
growths of rushes their roosting places, marked by broken, trampled 
vegetation and great piles of excreta, were found frequently; and 
goose tracks were often seen in small channels and runs through the 
marsh, so fresh that mud stirred up as the geese passed was still held 
in suspension in the water, but the birds themselves kept well hid- 
den. By molting at this early date the wing feathers of the adults 
were renewed by the time the young were able to fly, and old and 
young were thus able to remain together. Geese begin to reappear 
on the marsh between July 1 and 4. and by July 10 small flocks with 
their musical call notes were again a familiar morning and evening 
feature of the life of the marsh. 
