53 



with fragments of pear, mixed with the remains of i dung 

 beetle (Geotrupes stercorarius) . 



Summary. — 8 contained insects of the injurious group; 

 i, beneficial group ; 6, indifferent group ; i, mollusc ; 2, earth- 

 worm ; 3, potato ; 6, wheat and oats ; i, maize ; i, fragments 

 of pear ; i, vegetable fibre. 



Field Notes. — 370. Oak Tortrix Moth. — Every summer, when 

 the caterpillars of the Green Oak Tortrix Moth [Tortrix viridana) 

 are devastating the oaks in the Forest of Delamere, flocks of 

 Rooks and Jackdaws congregate in the infested trees and may 

 be seen busily engaged in searching for insects ; I ; have come 

 to the conclusion, therefore, though it is possible that I may be 

 wrong, that these birds feed extensively upon the larvae and 

 pupae of this destructive insect. Other moth larvae are un- 

 doubtedly present upon the trees at the same time but it is- 

 reasonable to assume that the birds are attracted by those 

 insects which occur in the greatest numbers. 



371. Potato Tubers. — Potato tubers are sometimes grubbed 

 up by these birds and carried away. This habit has been 

 observed at Bull Bay, Anglesey, and in one locality in Cheshire ; 

 but this trait cannot, I think, be considered at all general, and 

 the harm done in this direction is scarcely worth consideration. 



372. Walnuts. — In Cambridgeshire I have seen them carry 

 off unripe walnuts, of which they seemed particularly fond ; 

 but this trait was confined to a few daring individuals and the 

 amount of damage was not of a serious nature. 



373. " Leather Jackets." — In the Gardeners Chronicle for 

 January 21 st, 1905, No. 943, pp. 34, 35, I dealt with '' some 

 new facts concerning the economy of- the Crane Fly (Tipula 

 oleracea) and its natural enemies." In this paper I en- 

 deavoured to show to what extent Rooks feed upon the 

 destructive larvae of this insect ', and as the facts are of 

 agricultural importance it has been thought desirable to 

 reproduce them in order that my observations may be as 

 complete as possible ; all the more so seeing that the post- 

 mortem records of this bird are so meagre. 



"Since the days when John Curtis published his Farm 

 Insects in i860, much has been written on the depredations of' 

 the Tipulae or crane flies, but comparatively little that is 

 new has since been added to the interesting account which 



