378 University of California Publications in Zoology [VOL. 11 



PAGE 



Examination of feces 437 



Quantity of food 440 



Capacity for good or evil as evidenced by the number of birds 



taking different kinds of food 444 



Pood of nestlings 447 



Variation of kind of food 448 



Variation in food according to time of year 450 



Variation in food habits according to locality 454 



Influence of age and sex on quantity of food 455 



Combination of field and laboratory work 456 



The relation of birds to insect outbreaks 456 



Verdict of ranchers as to the value of the western meadowlark 462 



A determination of the economic status of the western meadow- 

 lark in California 466 



Suggestions for the protection of crops 474 



Recommendations as to legislation 475 



Some interesting side-lights on the investigation 477 



Parasitism 477 



Malformation 477 



Albinism 478 



Incubation and moult 478 



The effect of systematic destruction on the numbers of meadow- 

 larks 478 



Natural death-rate 479 



Do protective adaptations of insects protect them from the at- 

 tack of birds? 480 



Availability as a factor in the kind and quantity of food of birds.. 487 



Solved and unsolved problems in economic ornithology 488 



Summary 490 



Bibliography 494 



Explanation of plates 504 



PREFACE 



The impetus given in late years to the study of the relations 

 of birds to agriculture in the United States is traceable to the 

 extensive work of the United States Bureau of Biological Survey. 

 From the organization of this department of the United States 

 Department of Agriculture, July, 1885, to December 31, 1911, 

 members of the Biological Survey have prepared and published 

 one hundred and thirty-one documents relating wholly or in part 



