( xxxiv ) 



bility " from a rejection, in cases where the state of the bird's 

 hunger at the time of the incident is unknown. A bird will 

 often accept eagerly a low-grade species when hungry enough, 

 or reject a favourite species when replete. 



The statement sufficiently explains many of the cases in 

 which individual birds of a species (perhaps caged) have been 

 seen to refuse what others (perhaps wild) have been known 

 to eat, and vice versa. 



(2) A bird, given a definite choice, either fails to exercise 

 it, as between the things he is hungry enough for, and merely 

 takes each as it comes, or, when he does exercise it, tends to 

 select the largest object that he is at the moment hungry 

 enough to eat ; e. g. an Amauris niavius may then be taken 

 in preference to a Precis cebrene. This accounts for much 

 that has seemed difficult, as in Colonel Manders' experiments 

 and my own earlier ones in which " nauseous " butterflies 

 were taken in apparent preference to pleasanter ones. 



The fact remains that my various birds (with the exception 

 of one probably specialised species — the ashy wood-swallow 

 may well be another) would only eat Amauris when hungry, 

 but P. cebrene nearly to repletion-point. That the advantage 

 may be a great one, sufficient to make the possessor 

 worth mimicking, is shown by the immense meals that are 

 sometimes eaten after the refusal of a low-grade butterfly; 

 e. g. forty butterflies including fourteen large Charaxes by a 

 roller after she had rejected a Mylothris, and thirty-seven 

 including twelve large Charaxes after her rejection of a Terias. 



All I need add here is that all the very varied animals on 

 which I was able to test the point showed marked preferences, 

 eagerly eating some species of prey when nothing would induce 

 them to eat other species, and that the preferences of my 

 captive birds were confirmed by wild birds and by each 

 other. 



OOier objections. — No one, I believe, who has closely and 

 continuously and frequently watched the " searching " 

 species that in tropical countries form so large a proportion 

 of the bird-population, as they climb in parties over the 

 trunks and twigs, peer into every cranny and inspect each 

 surface of each leaf, pull off or prise aside small loose scraps 



