244 BIRD BEHAVIOUR 



butterflies, refused the Danaids after pincMng 

 them with the tip of the bill, and treated a cigar-end 

 in the same way. The latter substance might have 

 been rejected by touch, but in the case of the 

 insects, as the bird ate other butterflies', it seems only 

 natural to conclude that it detected an objectionable 

 scent by means of the posterior nares; taste was 

 out of the question, as the tongue in the Hornbills 

 is so very short, and the beak, for some inches from 

 the tip, as dry and horny inside as out. ^ 

 {IWith regard to the very birds in which one 

 would expect scenting powers to be particularly 

 well developed, the Vultures, all the evidence is 

 against this, those who have experience unanimously 

 declaring that a carcase if well covered over is not 

 detected by them ; and in Darwin^s classical experi- 

 ment with a hungry Condor the bird did not 

 appreciate the nature of the contents of a paper 

 parcel of fresh meat till he touched it with his 

 beak, in which close proximity the odour of raw 

 flesh would no doubt be detected by a human nose. 

 In spite of the less elaborate structure of the 

 internal ear, and of the absence of an external one 

 altogether, there is no doubt that the hearing of 

 birds is at kast as good as our own, and in many 

 cases possibljr' even better. This is particulariy 

 remarkable, because not only is the outer ear or 

 auricle wanting, but the ear-hole itself is generally 

 overhung by a dfense patch of short and very firmly 

 rooted feathers, the ear-coverts, which sometimes 

 remain when the rest of the head is naked^ as in the 



