8 IS THE SPARRO W DESTR UCTIVE ? 



such as Caradri?2a ciibiailaris^ the p&le mottled willow 

 moth of Curtis ('Farm Insects/ p. 308), identified for 

 me by Mr. C. G. Barrett and the Rev. J. Hellins.* 



If one-fourth of the young sparrows hatched in 

 England are fed for ten days on 14 caterpillars apiece, 

 it is easy to make a calculation of how many they 

 would eat in a large agricultural county like Norfolk. 

 Norfolk contains 800 parishes : say that 800 young 

 sparrows are annually hatched in each parish ; that 

 gives us a total of 640,000 sparrows. If one-fourth of 

 them are fed on caterpillars, we should have 22,400,000 

 of these destructive creatures eaten in this one county 

 alone, every year^ by sparrows. So that there is a 

 very nice balance to adjust in a matter which the most 

 expert observer might find difficult. On the one hand 

 the young sparrows are fed on a great many cater- 

 pillars ; on the other hand they are fed with grain, 

 but this is mixed with weeds and other vegetable matter. 

 Again, there is a side light in which to look at the ques- 

 tion : — If the sparrows were dead, how many of these 

 caterpillars would be eaten by other small birds 1 We 

 may be quite sure that a [considerable portion of them 

 would not be eaten, unless chaffinches and greenfinches 

 become more numerous than they are now ; and if this 



* Several Continental naturalists include the cockchafer in the 

 sparrow's food ; but I think that most likely the ' chovy ' [Phyllo- 

 periha) is intended as well. Professor Newton (Yarrell, British 

 Birds, part x., p. 92) and Mr. H. Stevenson {Birds of Norfolk, 

 i., p. 211) tell us that the sparrow eats ' chovies,' P. horticola, 

 and the former says he has seen their mouths literally crammed 

 with them ; and Mr. John Curtis says that he has known of 

 sparrows gorging themselves to such an extent with ' chovies ' as 

 to be unable to fly [Fartn Insects, pp. 220, 510). Prof. Newton says 

 it begins to come out of the ground towards the end of May, and 

 the perfect insect carries on its ravages until July (Prof. Newton, 

 Inlitt.). 



