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



Plate IV. 



*lffl 



MHi 





MM 



Fig. 1.— Group of Sick Birds. 

 These birds were collected on the Bear River Flats and now await transfer to pens. 



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



The building is a temporary structure erected as a field laboratory. Other experiment pens in 

 use at this time are not shown in the photograph. 



