such as Caradrina cubicularis, the pale mottled willow moth of Curtis ('Farm Insects,' p. 308), identified for me by Mr. C. G. Barrett and the Rev. J. Hellins.[1]
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 caterpillars; 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 question:—If the sparrows were dead, how many of these caterpillars would be eaten by other small birds? 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' (Phyllopertha) 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 (Farm 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, In litt.).
