8 BULLETIN 217, U. S. DEPARTMENT OF AGRICULTURE. 
migrants gathering from near-by breeding grounds to feed, molt, 
and pass the early fall in the accustomed security of the great marshes. 
Large numbers of the birds found dead in July and August un- 
doubtedly have come to these marshes from other localities. In the 
brief account given of the history of the trouble it was shown that 
sick birds have occurred for a longer time than is commonly believed- 
In fact there can be little doubt that for many years under certain 
conditions a few sick birds have been present annually in alkaline 
pools and on mud flats bordering the mouths of the rivers. Thesudden 
increase in the mortality may be explained by the increased amount 
of water used for irrigating purposes. Undoubtedly the quantity of 
water reaching the lake through the rivers has been greatly reduced 
within the past 15 years. Alkalis and salts are leached from the soil 
by irrigation and carried off in the drainage to be deposited in the 
deltas of the rivers and elsewhere. An instance of this leaching is 
shown in the freshening of the ground water north of Bear River near 
Corinne. Under these changing conditions disaster came with the 
dry summer of 1910. 
SUGGESTED REMEDIES. 
Fresh water is the only remedial agency yet discovered for dealing 
with this mortality among waterfowl. In the marshes at the mouth 
of the Jordan River the problem may be considered as settled. 
Water from the Jordan is carried through the marsh in a series of 
canals, and as long as it is abundant these are kept full. When the 
supply fails, as it may in dry years, the marsh can readily be drained 
and dried. Under normal conditions there are only two points in 
these channels where stagnation and consequent mortality may occur 
to any extent; namely, near the Mallard Holes and about the Duck 
Puddles on the west side. On the flats below the dams on the lake 
front a small number of birds will undoubtedly die, even though the 
marshes are drained, but under present conditions this can not be 
remedied. 
At the mouth of the Weber River the situation is more difficult. 
Here the north channel at present marks the true course of the 
stream, though in late summer there is little water, as the whole 
supply is diverted near Ogden for irrigation purposes. Toward the 
lake are level flats with shallow pools of water connected by a very 
slight current, or cut off in places from the main body. The south 
channel has higher banks and runs as a narrow stream supplied by 
waste water from irrigation ditches. Few, if any, sick birds occur in 
this channel, as it is deeper and well drained. However, the ducks 
elect to use the shallow flats along the north channel, and probably 
less than 10 per cent of the birds that gather there during the summer 
are alive by the opening of the shooting season on October 1. If the 
a 
