THE FINCHES 121 



instance, the greenfinch, bullfinch, linnet, twite, redpolls. Most of 

 these, however, vary the diet with insects, especially in the earlier 

 stages, whilst the hawfinch, sparrow and tree-sparrow adopt this 

 regime, if not entirely, at least as a staple. To these, according to 

 Naumann and others, the chaffinch is to be added ; but Fatio l 

 declares the young of the latter to be fed, at a later period, with 

 seeds disgorged from the crop, and Bailly 2 also says the same thing, 

 or, at any rate, that triturated seeds are given them. No other 

 observer, as far as I am aware, has remarked this, but a very good 

 provisional rule in the estimation of evidence, is to be more impressed 

 with affirmative than with negative statements. If it is only some- 

 times that the chaffinch does this, that makes it all the more 

 interesting. 



Some recent observations by Mr. Farren would seem to favour 

 this latter conclusion, since the young were then fed, though fledged 

 and almost ready to fly, on green caterpillars and some other insects, 

 a skipper butterfly, on one occasion, being amongst the number. The 

 element of doubt, however, is perhaps not entirely eliminated, Mr. 

 Farren's words being as follows : " It was not easy to identify the 

 nature of the food, since generally it was carried quite hidden from 

 sight, in the mouth or throat, and it was only as it was regurgitated, 

 just before delivery to the young, that I caught sight of it. I after- 

 wards found some pieces which had been dropped in the nest, by 

 which I was able to confirm my previous identification." But if the 

 possibility of the food having sometimes been not insects, but grain, 

 is here excluded (which it, perhaps, is not absolutely), we are still left 

 in doubt whether the caterpillars had first been swallowed, or were 

 only, or only sometimes, brought in the mouth or throat, as suggested. 

 If the former, or even if the latter, then we may perhaps see a step in 

 a process of transition, the course of which would be insects brought 

 in the beak mouth throat swallowed first and regurgitated- 



1 Oiseaux de la Suisse. * Ornith. de la Savcrie. 



3 Country Life, July 13, 1907. 



