8 University of California Publications in Zoology [Vol. 11 



grasshoppers. Most of the birds were collected where grass- 

 hoppers were abundant, but a few were taken in non-infested 

 districts so that a comparison might be made. All were col- 

 lected between the hours of eight and four. The accompanying 

 table, on page 9, gives the results of the stomach examinations. 



The burrowing owl must be considered the most efficient de- 

 stroyer, since parts of twenty-eight grasshoppers were found 

 in the one stomach examined. Blackbirds and meadowlarks, 

 however, because of the large numbers of individuals, were 

 doing the most effective work. 



The comparative destruction of grasshoppers per day by 

 single individi^aLs, and by the total number of each species, is 

 represented in the following table: 



COMPARATIVE DAILY DESTRUCTION OF GRASSHOPPERS BY 

 BIRDS 



Relative destruction 

 of dififerent species 

 represented by lines 



