AUGUST 149 



XXXVII 



All persons directly interested in agriculture, as well 

 as those indirectly concerned for the welfare The Food 

 of that industry as a source of food supply, <rf"5Kook 

 may read with advantage Dr. W. E. Collinge's paper in 

 the Journal of the Ministry of Agriculture for December 

 1920. Dr. Collinge has applied intensive study during 

 many years to analysing the diet of our commoner 

 birds. He estimates that 10,000 rooks will consume in 

 the course of a year 232 tons of food. Scrupulous 

 examination of the contents of the crops of hundreds 

 of these birds at different seasons has led him to 

 conclude that the said weight of food would probably 

 be made up in the following proportions : 



Grain, 80 tons 



Potatoes and roots, . . . . 32 

 Beneficial insects, . . . 7^ 



Injurious insects, slugs, snails, etc., . 65 



Miscellaneous, .... 47 



Total, . 232 tons 



Assuming this estimate to be aproximately correct, the 

 balance appears considerably to the detriment of the 

 rook's character from the farmer's point of view ; but 

 the question remains Supposing the 10,000 rooks had 

 not consumed 65 tons of injurious insects, would these 

 insects have destroyed as much agricultural crop as 

 the rooks did ? Dr. Collinge thinks they would not, as 

 a considerable percentage of the insects would have 

 been eaten by starlings, lapwings, and other birds. 



