BIRDS AND INSECTS 161 



and crops. To deliver a true verdict on the evidence 

 that may be collected as to the food of any one of these 

 omnivorous birds is by no means an easy matter, 

 because the food varies in different months of the 

 year, and even in the same month in different parts 

 of the country. But a verdict that is based upon 

 observations of the birds feeding at a distance in a 

 field or upon impressions and traditional prejudices 

 of the country-folk may be entirely misleading, and 

 if it is followed by active measures, or the ruthless 

 shooting down of the species, may lead to irreparable 

 mischief. 



In order to obtain some trustworthy evidence on 

 this matter a committee was appointed by the British 

 Association in 1908, and this committee, with the 

 co-operation of the Board of Agriculture and with the 

 assistance of grants of money obtained by the board 

 from the Commissioners of the Development Fund, 

 and smaller grants made by the British Association, 

 undertook the scientific investigation of the contents 

 of the crops and gizzards of our three most abundant 

 omnivorous birds, the rook, the starling, and the 

 chaffinch. 



Reports on these investigations were published as 

 a supplement to the Journal of the Board of Agri- 

 culture in 1916, but in respect of the work done in 

 the University of Manchester, the report then pub- 

 lished was only an interim report, the results of 

 the investigation not being completed or fully tabu- 

 lated. 



To furnish the requisite material, a number of birds 

 were shot by the correspondents throughout the year 

 and forwarded to the investigators, who carefully 

 examined and recorded the contents of the crops or 

 (in the case of the rook) the gizzards. The animal 

 food was classified into two groups: the insects, 



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