Birth in I?eIation to tJieir Prey. 105 



tion to the commonest, insect that they are at the time 

 hungry enouorh for. Absorption in the search or watch for 

 one particuhu' kind of insect is, I believe, fairl}'' frequent, 

 and it probably pays the bird ; it certainly accounts for a 

 number of the instances of neglect we witness. And the 

 selection of the largest insect present that the bird is hungry 

 enough to eat — resulting, it may be, in the taking of an 

 Amauris dominicanus in preference to the far higher-grade 

 but smaller Precis cehrene — is, as I have seen in both tame 

 birds and wild, the rule where the bird lias a choice and 

 troubles to make it. 



It is interesting to inquire how birds come to know that 

 some Insects may be eaten with impunity at a given moment 

 and others not. Prof. Lloyd Morgan's experiments on young 

 birds are well known. He found no indication that they 

 possessed any inherited instinctive knowledge of what could 

 and could not be eaten. I have myself carried out a similar 

 series of experiments on some of our African birds — with 

 the same result. Even the experiments I have described 

 above contain some evidence bearing on the point, in the 

 trial of a lump of earth and excrement by the Crowned 

 Hornbill, its rejection after swallowing it of a Mijlothris, in 

 the actual nauseation of the Wood-Hoopoes by insects that 

 they had eaten, and, for that matter, in the continual rejec- 

 tions that took place after tasting (see, too, experiment 560). 

 I have, in all my experiments, come across no evidence of 

 visual instinctive recognition, but plenty of evidence to the 

 contrary. Whether rejection by taste is equally non-in- 

 stinctive is another matter. Watching a' bird going through 

 a long experiment, and noting the accuracy and relative lack 

 of hesitation with which he pronounces his decision on insect 

 after insect, by taste, one is almost convinced that the selection 

 is instinctive. Yet, in view of one's experience with very 

 young birds, and of such mistakes as those made by the 

 Wood-Hoopoes and (h'owned Hornbill, it is probably more 

 correct to say that, with practice, recognition of deeper 

 qualities by taste becomes instinctive, just as the playing of 

 the piano does, only far more easily. 



8 



