382 University of California Publications in Zoology [Vol. 11 



conception as to the utility of birds, it is high time we sought 

 to destroy it and to establish truth in its stead. 



The economic relations of birds must necessarily become more 

 and more important. As they do so, the extensive study of the 

 past few years will give way to the intensive study necessary 

 to solve the greater problems of the future. Probably no one 

 thing will play a greater part in the conservation of wild life 

 than will this intensive study. Recognition of the economic value 

 of a single bird will stimulate interest in the protection of all. 



This work is published, therefore, in the hope not only that 

 the facts and data here presented may be of general interest and 

 of value to future workers in economic ornithology, but that it 

 may be a factor in promoting the conservation of wild life in 

 California, a state which still possesses enough of its original 

 fauna to make its conservation important and eminently 

 desirable. 



INTRODUCTION 



Doubtless if our knowledge were not so limited we might 

 be able to find a use for most living things. As it is, we designate 

 animals as useful, neutral, or injurious because of their effect 

 on ourselves or oiir interests. A thorough study of the inter- 

 relations of such animals often reverses our original decisions 

 regarding them. Not many years ago insects as a class were 

 called injurious because some of them destroyed certain crops. 

 Today only a part of the insects are considered destructive, and 

 we are yearly finding that others are of neutral or beneficial 

 character. 



Not many years ago birds were looked upon either as pests 

 or as marks for the gunner. Today most of them are looked 

 upon as valuable assets of the agriculturist. As science in the 

 past has slowly lifted us to a plane where we study the complex 

 interrelations instead of the single and obvious ones, so in the 

 future we may expect that more and more each form of life will 

 be found to fill a particular niche in its environment better than 

 anv contiguous form. 



