1914 J Bryant, Birds as Grasshopper Destroyers. 169 



An estimate of the numbers per square yard in the infested areas 

 was obtained by counting the numbers disturbed by the observer 

 at each step. Little damage could be noted where grasshoppers 

 were less than fifteen to the square yard. Where damage was 

 greatest alfalfa fields averaged about twenty-five to the square 

 yard. In some pasture land along the irrigation canals the number 

 was estimated at thirty per square yard. 



This will give the reader an idea of the conditions existing at the 

 time observations hereafter recorded were made. 



The neighborhood of Los Banos, largely due to the great irriga- 

 tion system and to the large amount of land which has been 

 'swamped,' supports a very large bird population. Water birds 

 and shore birds are very abundant along the canals and in the 

 marshes, whereas the pasture lands, the alfalfa, and the trees, 

 furnish food and cover for many land birds. During a week's stay, 

 July 10 to 17, 1912, twenty-two species of water and shore birds 

 were recorded and forty species of land birds. Censuses taken 

 indicated that the Bicolored Redwing was the most abundant bird 

 and that the Cliff Swallow, Barn Swallow, Western Meadowlark, 

 Linnet, Western Kingbird, and California Shrike, listed in the 

 order of their abundance, were also common. 



Observation showed that the following species of birds were 

 feeding on grasshoppers. Only those birds actually seen with 

 grasshoppers in their bills were recorded. 



Western Meadowlark, Sturnella negleda. 



Bicolored Red-wing, Agelaius phoeniceus californicus. 



Brewer's Blackbird, Euphagus cyanocephaliis. 



Bullock's Oriole, Icterus bullocki. 



Arkansas Kingbird, Tyrannus verticalis. 



California Shrike, Lanius ludovicianv^ gambeli. 



English Sparrow, Passer domesticus. 



Although observation in the field furnishes some evidence as to 

 the kinds of birds feeding on an insect and the quantity consumed, 

 yet it is on stomach examination that we must depend for accurate 

 evidence as to the numbers of insects taken. In this instance a 

 determination of the numbers of grasshoppers taken by the bird 

 was made easy because of the presence of the mandibles of the 

 insects — hard parts which remained undigested. Experiments 



