18 BULLETIN" 672, U. S. DEPARTMENT OF AGRICULTURE. 
storm that covered the mountains with snow. After the storm the 
sun came out warm and bright, and a number of the swallows gath- 
ered about the shallow pools on the barren flats. Apparently in play, 
they were forming mud pellets such as they use in building their 
nests. The strong alkalis concentrated in this surface mud affected 
many of these birds severely, so that during the next few days I picked 
up several swallows about the laboratory unable to fly, and there is no 
means of telling how many escaped unnoticed in the salt grass The 
affection in the cases examined was similar to that found in the ducks. 
Though mortality among ducks and other birds ceases when the 
fall water fills the rivers, yet many birds are still more or less seriously 
affected. During the hunting seasons in the years 1914 to 1916, 
inclusive, the writer examined many hundreds of ducks as they were 
cleaned and prepared for the market in the duck houses at the gun 
clubs on Bear River. In birds examined during the first week or 10 
days there was severe irritation in the intestinal tract in almost every 
case. After October 10, there was a great influx of migrants from 
the north. These birds were shot in many cases before they had 
been long on the marshes, but still many of those examined had the 
intestine much irritated. In cases of severe affection that do not 
terminate fatally individual ducks use up their stores of fatty tissues 
while recovering from the duck sickness and become thin and poor 
in flesh. When shot in this condition they are culled by the duck 
pickers as unfit to eat. I was told by men familiar with conditions 
that many more ducks are thrown out now than previous to 1910. 
Certain observations made by the writer seem to prove this. In 
1916 sick ducks were last found in numbers in the eastern end of 
North Bay. After the hunting season opened a larger percentage of 
culls was noticed among the birds killed in this area than elsewhere. 
REMEDIAL MEASURES. 
Fresh water is the only agency that has been found of value in 
combating the duck sickness. Birds slightly affected, and even 
many entirely helpless, recover in almost all cases when given 
plenty of moderately fresh water to drink. With an abundance 
of good water in the marshes sick ducks are infrequent, as when the 
bays are well filled and well drained many birds that become affected 
recover in a few days. For remedial agencies, therefore, measures 
must be adopted that tend to supply fresh water or to drive ducks 
out from areas where they are liable to obtain alkalis in harmful 
quantity. Three methods of treatment that promise success in 
dealing with this trouble are concerned with (1) increasing summer 
water in streams, (2) draining affected areas, and (3) collecting sick 
birds for treatment. These methods as outlined in the following 
pages will prove applicable also in areas outside of Utah where birds 
are subject to the duck sickness. 
