Bui. 672, U. S. Dept. of Agriculture. 



Plate I. 



Fiq. 1.— Ducks Dead from the Duck Sickness. 

 Photograph taken on the North Channel at the mouth of the Weber River, Utah. 



Fiq. 2.— View of Drying Mud Flats at the Mouth of Bear River, Utah. 



Ducks are made sick here by alkalis taken into solution when these areas are flooded by rising 



or shifting water. 



