490 University of California Publications in Zoology [Vol. 11 



The exact relation which birds bear to the control of insect 

 outbreaks remains to be worked out. There are a number of 

 factors which tend to bring back normal conditions. Whether 

 birds, parasitic insects, weather conditions, or other factors are 

 of prime importance is a problem yet to be solved. The begin- 

 ning has been made and significant evidence adduced. A compre- 

 hensive study of this problem would do much towards solving it. 



The amount of benefit to be derived through the destruction 

 of weed seeds is still a debated question. When such efificient 

 measures as the weed cutter and the mowing machine can be 

 brought into use, the amount of good accomplished in a bird's 

 destruction of weed seeds is minimized. A weed-seed eater must 

 be considered a less valuable bird than an insect eater where 

 weeds are more easily controlled than insects. Better insect 

 control measures will likewise make the value of insectivorous 

 birds less apparent. The inherent value, nevertheless, remains 

 unchanged. Common sense would seem to dictate the making 

 use of natural control measures to the greatest extent possible. 

 Herein lies the justification for emphasis on the value of birds 

 as insect and weed-seed destroyers. 



SUMMARY 



Owing to the constant complaint of ranchers as to the depre- 

 dations of birds and attempted legislation to take protection 

 away from certain non-game birds, the California State Fish and 

 Game Commission, in co-operation with the University of Cali- 

 fornia, has undertaken a thorough, scientific investigation into 

 the relations of birds to agricultural interests. The western 

 meadowlark (Sturnella neglecta), owing to its depredations in 

 sprouting grain fields, has been the first bird to be studied. 



A study of the history of methods used in economic ornith- 

 ology has shown that the time has come when circumstantial or 

 partial evidence as to the food of a bird is insufficient evidence 

 on which to determine its economic status. Nothing short of a 

 knowledge of a bird's food for the whole year, a knowledge of 

 its depredations, and its whole life history, allowing a balance 

 of all of the benefits conferred against all of the injuries done, 

 is now demanded. 



