1914] Bryant: Economic Status of the Western Meadowlark 461 



COMPARATIVE DAILY DESTRUCTION OF GRASSHOPPERS BY BIRDS 



Species 

 Anthony Green Heron 



Kildeer 



Burrowing Owl 

 Western Kingbird 

 Black Phoebe 

 California Horned Lark 

 Bicolored Eed-wing 

 Western Meadowlark 

 Bullock Oriole 

 Brewer Blackbird 

 English Sparrow 

 Cliff Swallow 

 California Shrike 



Relative 



destruction by 



different species 



represented 



by lines 



Class A represents birds taking an average of over 50 grass- 

 hoppers per day; class B, 25-50; class C, 10-25; and class D, 

 fewer than 10 grasshoppers. 



The comparative numbers of the different species were calcu- 

 lated by averaging censuses taken and by using the average per 

 mile as a multiplier. Although not accurate, the table never- 

 theless demonstrates the fact that such birds as the bicolored 

 red-wing and the western meadowlark, birds of small capacity, 

 because of their greater numbers, far outrank in efficiency birds 

 with larger individual capacity. 



The fact that the western meadowlark, or any bird, turns 

 its attention to the insect most abundant only emphasizes its value 

 as a balancer. If meadowlarks took no greater proportion of 

 insects when they are in abnormal numbers than when they were 

 in normal numbers, they would play a decreasing part in restoring 

 a balance. Since they do change the proportions of food to meet 

 the fluctuations in the number of insects, they must be consid- 

 ered an important factor in the restoration of normal conditions. 



