108 Birds ill Relation to their Prey. 



so frequently exchanged by birds, the actions of the male in 

 courtship and of both sexes in the training of the young, the 

 warnings against enemies and the threats and reminders to 

 the same, and the signals by which birds keep in touch with 

 one another, and we have a language that for all practical 

 purposes is tolerably complete. 



Behaviour in face of a snake (experiments 537 and 554) 

 — not that an Amphisbsenid is a snake ! — the close study 

 of the appearance of a rejected Amauris by Irrisor in 

 508, and the deception of birds by resemblances in their 

 prey (experiments 507, 509, 511 (perhaps), and 529), are, I 

 think, almost the only remaining points to which I need call 

 attention. The last point has been illustrated in numerous 

 other experiments, and, taken together and in due relation 

 to the fact that the same appearance is often brought about 

 in unrelated prey by utterly different pigments, they suggest 

 that birds see colours very much as we do. That some 

 species are very blind, and others sharp-sighted, in relation 

 to motionless objects (all depending on their general habits), 

 I had, I think, little or no evidence in these experiments, but 

 much in others. Both this fact and the above-mentioned 

 study of the Amauris have an interesting bearing on the 

 question of hypertely. Of the other senses of birds, smell 

 only is worth referring to here. The ridiculously short 

 tongue of Lophoceros and other hornbills, and the fact that 

 they, nevertheless, base their acceptances and refusals on 

 tastings performed with the very tip of the long bill, sug- 

 gests that we have here a case analogous to smelling rather 

 than true tasting. I have seen short-billed birds, on the 

 other hand, bring the tips of their tongues into actual con- 

 tact with the objects tested. That even these birds appreciate 

 odours — though they do not, like mammals, use them for re- 

 cognition — is shown by the behaviour of Crateropus in experi- 

 ment 564 (a very extreme case, of course) and by the fact 

 that my Swallows showed discomfort when strong-smelling 

 insects (such as the moth Xantliospilopteryx) were brought at 

 all close to them. 



