394 University of California Publications in Zoology [VOL. 11 



have seen a number of the leading magazines take up the subject 

 of the economic value of bird life, and with illustrated articles 

 they have brought to the attention of many the value of birds 

 to the farmer. 



Largely because of their depredations, the demand for an 

 intimate knowledge of the food of birds has become very pressing, 

 and yet it is interesting to note that attention to the economic 

 side of ornithology was not aroused by the depredations of birds, 

 but by the depredations of insects. 



A comparison of the methods used up to the present will 

 clearly show the progress which has been made in the science of 

 economic ornithology. Such a comparison is afforded by the 

 following sequence of methods used in determining the economic 

 value of birds: 



Sequence of methods used in determining the economic value 

 of birds : 



1. Observational notes on the food of birds. (Wilson, 1808- 

 1814; Audubon, 1827-1838.) 



2. Critical observational study of the food of birds. (Le 

 Baron, 1855; Holmes, 1857; Weed, 1903.) 



3. Examination of the stomach contents of birds. (Jenks, 

 (King, 1883.) 



4. Experimental feeding of captive birds. (Treadwell, 1859.) 



5. Observation plus stomach examination. (Aughey, 1878; 

 Judd, 1902.) 



6. Observation plus stomach examination plus experimenta- 

 tion. (Forbes, 1903 ; U. S. Biological Survey.) 



Similar progress can be noted in the methods used in de- 

 termining the food of birds. Their sequence has been as follows : 



1. Investigation of food with no reference to time or locality. 

 (King, 1883.) 



2. Investigation of food at time and locality of depredations. 

 (Forbes, 1903; Wilcox, 1892; Aughey, 1878; Bryant, 1911, 

 1912d.) 



3. Investigation of food according to the month, regardless 

 of exact locality. (Jenks, I860; Beal, 1907, 1910.) 



