v,,l 1!( ^ x | Recent Literature. 135 



the time of the Mission f.it In rs," lie says, "when grasshoppers were first 

 recorded as giving trouble, these insects have continued their ravages. 

 'I'Ik- bird population during that time has undergone a considerable change. 

 Certain water- and shore-birds, many of (hem known to be efficient 

 grasshopper destroyers, and especially important because of their migra- 

 ior\ habits, have been greatly reduced in numbers. On the other hand 

 certain land birds, owing to a bet ter food supply and cover, have increased 

 in number. Perhaps the most notable example of this increase is to be 

 found in the meadow lark, a bird w hich feeds almost entirely on grasshoppers 

 when they are abundant. It seems reasonable to believe that the increase 

 of birds has in part, at least, paralleled whatever increase of grasshoppers 

 may have been due to the increased food supply furnished by man. But in 

 spite of what the birds have accomplished in the destruction of these insects, 

 they continue to give trouble. Consequently we should not be justified 

 in saying that birds are capable of controlling all grasshopper plagues so 

 as to prevent damage." (p. 13.) 



"The average number of grasshoppers, when in normal numbers, per 

 square yard probably does not exceed two or three, and as a rule is probably 

 Less. The bird population, though taking but a tenth as many grasshoppers 

 at such a time, would be taking a far greater percentage of the total number 

 of these insects than when taking the numbers found to be consumed during 

 the outbreak. A smaller number of grasshoppers destroyed at the time of 

 minimum numbers has a more important bearing on the prevention of an 

 increase than a larger number destroyed at the time of maximum numbers. 

 We can safely infer, therefore, that the regulative influence of birds is just 

 as important throughout the year as during an insect outbreak, or even 

 more important." (p. 16.) This conclusion agrees with that reached by 

 Professor F. E. L. Beal, from a lifetime's work in economic ornithology. 

 (See Yearbook U. S. Dept. Agr. 1908, pp. 343-350.) 



However, Mr. Bryant's researches give proof of what lias been questioned 

 by some, namely that birds increase in numbers in areas severely infested 

 by some insect pest, and that they vary their diet to include an abnormal 

 proportion of the over-abundant species. " The investigation showed that 

 the birds in the vicinity of the outbreaks changed their food habits, in that 

 they U-<\ on the insect most available. The fact that meadowlarks neg- 

 lected their usual percentage of ground beetles and fed almost entirely 

 on grasshoppers can be explained in two ways. Either the grasshoppers 

 were taken in preference, or they were taken because they were the most 

 easily obtained. The large number eaten by the killdeer, and by the 

 Anilio'iN green heron, horned lark, ami oriole demonstrates this point, for 

 the recorded food of these birds under other conditions does not show so 

 large a percentage of grasshoppers." 



" Undoubtedly birds Hocked to the infested areas. brewer blackbirds 

 were seen Hying out from the ranch houses to the infested areas to feed. 

 Large flocks of bicolored red-wings fed almost entirely in the areas where 

 grasshoppers were abundant. A census of birds taken in infested areas, 



