Observations on the Cuckoo. 327 



that all the more typical finches (as the linnets, siskins and 

 goldfinches, canaries, and true grosbeaks), which, in the adult 

 state, subsist wholly and solely upon vegetable food, always 

 bring up their own young exclusively upon semi-prepared 

 vegetable diet ejected from their own craws; and, therefore, 

 that any of these birds should ever feed a young cuckoo upon 

 insects and caterpillars, which themselves never touch nor feed 

 their own young with, is a far more extraordinary fact than 

 that those finches which in the adult state are partly insecti- 

 vorous (as sparrows, buntings, and chaffinches, to which last 

 group the typical appellation jPringilla has been injudiciously 

 restricted # ) should do the same, as these latter birds naturally 

 bring up their own young entirely upon insect food. I would 

 recommend, however, those who may be fortunate enough to 

 have the opportunity, to certify the fact more thoroughly by 

 placing a cuckoo's egg in the nest of a goldfinch, linnet, or 

 green grosbeak, and to leave the young cuckoo, when hatched, 

 entirely to the care of these non-insect-eating birds. 



It would certainly be one point gained, if we knew, as 

 at present we have every reason to believe, that any sort 

 of small bird will hatch and bring up the cuckoo; and this 

 would seem to render it more especially remarkable, that only 

 one or two particular species (namely, the ground pipits, water 

 wagtails, and somewhat less frequently the hedge chanter, all 

 insect-eating birds, by the way) should so usually be selected 

 for this purpose, that the occurrence of the cuckoo's egg 

 in the nest of any other sort of bird may almost be con- 

 sidered an exception to a general rule. Is it, however, be- 

 cause the nests of these birds are particularly easy to find ?f 

 for such is certainly the case ; and yet the cuckoo's egg has 

 never (that I am aware of) been found in a chaffinch's nest, 

 which is frequently also a very easy one to find.:): I know this 

 fact, however, from repeated experiments, that the chaffinch 

 will not unfrequently turn out any small egg that has been 

 placed along with her own; but, whether she would so serve the 

 cuckoo's egg, remains to be ascertained. Mr. Denson remarks 

 (in p. 293.), that " it may be that the instances, never known 

 of by man, of the cuckoo depositing its eggs in nests from 

 which the owners of that nest discarded it, may be more nu- 



* Coccothraustes I conceive to be the most typical form among the 

 finches. 



+ Mr. Yarrell informs me that he is of this opinion. 



4: Since writing this, I have been so fortunate as to obtain a well 

 authenticated instance of the cuckoo's egg occurring, alone, in a chaffinch's 

 nest. The nest was robbed. Why, therefore, does it not more frequently 

 occur in the nest of this species ? 



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