THE DEVELOPMENT OF ECONOMIC ORNITHOLOGY. 19 



printed shortly after the publication of a remarkable article 

 by Professor J. W. P. Jenks, in which an elaborate study of 

 the food of the robin was recorded. In this study the modern 

 method of examining the contents of the alimentary tract and 

 estimating the ratios of the food elements found was em- 

 ployed, apparently for the first time in any elaborate way. 

 During the same year (1858) that Professor Jenks was making 

 his investigations, another Massachusetts man, Professor D. 

 Treadwell, made some remarkable observations upon the 

 amount of food required by young robins, the results of 

 which have often been quoted. 



During the decade from 1860 to 1870 there was a great 

 deal of discussion regarding the influence of birds upon agri- 

 culture. The transactions of the various agricultural and 

 horticultural societies and the agricultural, horticultural, and 

 entomological journals of this period contain frequent references 

 to the subject. The statement by Dr. B. D. Walsh, the first 

 State Entomologist of Illinois, that birds were of doubtful 

 value because of the parasitic insects they devoured, led to 

 much comment ; this statement is discussed in Chapter VII. 

 of the present work. 



It was during this period that Professor Samuel Aughey, of 

 Nebraska, began his remarkable investigation of the relations 

 of birds to outbreaks of Rocky Mountain locusts, the results 

 of which are summarized in Chapter VI. herewith. These 

 observations were not published, however, until near the close 

 of the next decade, 1878. This was the most important 

 study of the subject carried on during the decade from 1870 

 to 1880, although before the close of this period Professor S. 

 A. Forbes, State Entomologist of Illinois and Director of the 

 Illinois State Laboratory of Natural History, had begun the 

 studies on which the classic papers published during the next 

 decade were based. During the early years of the next 

 decade Professor Forbes published several papers which may 

 fairly be said to furnish the basis for the modern development 



