386 University of California Publications in Zoology [^OL. 11 



be seen, a bird has a certain value to society that cannot be 

 reckoned in dollars and cents. 



Some entomologists, seeing in insecticides the only successful 

 control measure against insects, are inclined to minimize the 

 value of such a natural control as birds. True it is that birds 

 apparently do not prevent or entirely control insect outbreaks, 

 for insects continue to ravage crops, no matter what the bird 

 population. However, if a certain number of insects cause a 

 certain amount of damage, it must follow that a diminution of 

 the number of insects causing damage must cause some dimin- 

 ution of the damage done even if it be not proportional. We are 

 justified in saying, therefore, that the fact that birds destroy 

 great numbers of injurious insects shows them to be important 

 agents in contributing to the safety not only of crops, but of all 

 vegetation. Judging from the great numbers of insects destroyed 

 at the time of an insect outbreak, we can safely infer that birds 

 may be instrumental in preventing the appearance of insects in 

 abnormal numbers, by helping to keep the numbers near the 

 normal, which we approximate by the phrase, "the balance of 

 nature. ' ' 



In this practical age almost everything is viewed from the 

 standpoint of dollars and cents. Hence it is desirable that we 

 study the economic value of birds. There is danger, however, 

 in so doing, for such studies may tend to minimize to a certain 

 degree a value which cannot be expressed in dollars and cents. 

 To say that a meadowlark is worth so many dollars to the rancher 

 each year may obscure its esthetic value. 



The strongest opponents of the theory that birds are bene- 

 ficial often emphasize the esthetic value. The following is a 

 quotation from one of these opponents (Baskett, 1910) : "Make 

 their song, beauty, grace and interesting habits a part of our 

 culture and their preservation part of our ethics, but do not 

 try to foist them on the farmer as an economic asset, for he 

 knows better in many cases. If the soldier can make better 

 marches under the martial influence of the 'spirit-stirring drum' 

 and * ear-piercing fife, ' so can the farmer gather inspiration from 

 the activity and cheerfulness of birds." 



