572 



GAME BIRDS, WILD-FOWL AND SHORE BIRDS. 



produce a perennial supply of duck food indefinitely. Some 

 of them now grow commonly in our inland waters, and others 

 have to be introduced. 



The Biological Survey recently has issued a very useful 

 circular written by Mr. W. L. McAtee, which describes and 

 illustrates wild rice, wild celery and pondweeds of the genus 

 Potamogeton. From this circular most of the information 

 given below regarding these plants is taken. ^ Mr. McAtee 

 finds by examining the stomach contents of many individuals 

 of sixteen species of game Ducks, taken in different parts of 

 the United States, that wild rice, wild celery and certain pond- 

 weeds collectively compose 25.31 per cent, of the total food. 

 The percentage of these foods found in the stomachs of the 

 different species is given in the following table : — 



' McAtee, W. L.: Three Important Wild Duck Foods, Bureau of Biol. Surv., U. S. Dept. of Agr., 

 Circular No. 81, 1911. 



