Bui. 217, U. S. Dept. of Agriculture. 



Plate 



Fig. 1.— Snowy Herons Dead from the So-Called ""Duck Malady.- 



Photograph taken September 22, 1914, at mouth of Bear River, Utah. 



Fig. 2.— Row of Experiment Pens at Mouth of Bear River, Utah. 



In these inclosures ducks were kept under experimental conditions. Similar pens were 

 stationed at other localities on the mud flats. 



