THE FINCHES 131 



since the former is the process by which insect food, more particularly, 

 is administered, both the one and the other are a survival, probably, 

 or continuance, of earlier dietary habits. 



How, then, did our finches, previously accustomed to bring their 

 young caterpillars or spiders in the bill, begin, instead, to regurgitate 

 seeds or buds, for them, from the crop ? Of course, a variation in the 

 diet of the old birds would be a motive for making a corresponding 

 change in that of the fledglings, though, by a conservative instinct 

 analogous to that by which ancient usage is preserved in legal or 

 religious rite and ceremony, this tendency might be resisted. Seeds 

 can be transported in the bill, as are grains of wheat and barley by 

 the house- and tree-sparrow, but, where they are small, this would be 

 a tedious process, nor would a number, perhaps, be so easy to carry 

 as a beakful of insects. If only the idea could have been hit upon 

 of bringing up the seeds again, at the nest, after they had been 

 swallowed afield, it would have been, for the Finch tribe now become 

 largely seed-eaters as the invention of fire to the contemporaries 

 of Prometheus. But how could it have been, or, rather, how was it ? 



As to this, young birds, especially when large enough to be active 

 in the nest, are very importunate for food. The parents are pressed 

 and worried, and often resist their endeavours by turnings and 

 motions of the head. In some of these, as the action seems an easy 

 one with birds generally, there may have been slight, involuntary 

 regurgitations, and, since the beaks of the young would be always 

 seeking those of the parents, these might have been taken advantage 

 of, sought again, expected, excited, till, finally, through stages which 

 I myself have no difficulty in imagining, and which may even be, to 

 some extent, seen, 1 the thing grew into a custom. Once established 

 by precedent, this method of giving the food, which allowed the 

 parents to feed upon it too, would have become more and more 

 congenial to them, till, in the end, they would have taken the 

 initiative, and satisfied, in this manner, not only the craving, im- 



1 As, for instance, with the cormorant. 



