268 SCIENCE PROGRESS 



We have to consider the harmful creatures they devour. 

 Can we destroy them easily? If so, then the good they do 

 must be discounted. In the case of voles and mice we must 

 acknowledge we cannot, and thus it seems the good done 

 must far outweigh the evil. 



There is no dispute about Owls. The Barn Owl (Strix 

 flammea, Linn.), the Short-eared Owl {Asio accipitrinus, Pallas) 

 live mostly on voles, long-tailed field mice, and small birds ; 

 the Tawny Owl [Syrnium aluco, Linn.) is a great devourer 

 of finches. The Long-eared Owl (Asio otus, Linn.) alone has 

 anything against it, as it is now and then. troublesome to the 

 gamekeeper. 



With the family Corvidae we come to a group subject to any 

 amount of discussion and divergence of opinion. Those that 

 are of economic importance are the Rook, Carrion Crow, 

 Hooded Crow, Jackdaw, Jay, and Magpie. 



The Rook is one of those birds about which we hear 

 incessant discussion. Many farmers seem inclined to favour 

 it. The Rev. H. Slater (2, p. 248) says : " This bird is rather 

 a problem at present. I have no hesitation in expressing my 

 belief that it is a most useful friend to agriculture on the 

 whole, if not allowed to increase in numbers abnormally" (the 

 italics are mine). Mr. Cecil Hooper (1, p. 80) mentions the 

 damage they do to fruit, eating green strawberries, cherries, 

 gooseberries, sometimes apples and pears, walnuts, cobs and 

 filberts, and records a case of their damage to raspberries at 

 Blairgowrie, in Scotland. He then says : " In order to keep 

 the number of rooks under control, the newly-fledged birds 

 in a rookery should be shot, say two out of each nest, in 

 order to make the number stationary and not increasing." 



In connection with the Rook, Mr. J. Gilmour's report (16) 

 must be quoted. He says as follows : " While I was prepared 

 to find that facts were all against the Woodpigeon, I was, I 

 confess, in hopes that our particular inquiries into the diet of the 

 Rook would clearly prove that, if not over-abundant, he might 

 to a considerable extent be a friend to the farmer. Judging 

 from the results of this special investigation, as tabulated, I 

 fear figures go badly against him." 



There is no doubt whatever that Rooks take a great deal 

 of seed-corn and even potatoes in dry weather. Attacking 

 stacked corn (16) is surely unusual. But, on the other hand, 



