The Senses 219 



tongues and ample membranes of the mouth, doubtless 

 possess this sense to a considerable degree, while in birds 

 which are exclusively fish-eaters we may expect to find 

 taste least developed, the character of their food pre- 

 cluding all need for this faculty. 



But from no bird is taste entirely absent, as we may 

 easily see by presenting some nauseous insect, which 

 will be instantly rejected with very evident signs of dis- 

 gust, the bird wiping its bill on a branch and shaking 

 its head violently. 



The sense of feeling, although much deadened by the 

 feathery and horny character of a bird's integument, is 

 most active at the tip of the tongue and the beak. At 

 the base of the feathers, especially those of the wings and 

 tail, tactile nerves are found, so that even a touch on the 

 tips of the feathers awakens a response in the nervous 

 system. 



The delicacy of the tactile touch is remarkable in those 

 long-billed birds which seek their food in the muddy 

 bottom of shallow water, detecting by means of their 

 sensitive bills the presence of worms and snails, aided 

 little or not at all by eyesight. In the woodcock and 

 apteryx this dependence on the senses of touch and smell 

 has even wrought a change in the position and character 

 of the eyes. The upper mandible of the woodcock is 

 probably unique in being so sensitive and mobile that the 

 distal third can be curved some distance upward, the base 

 of the two mandibles remaining close together. This is 

 an admirable provision by which, when the bird has driven 

 its beak deep down into the moist soil, it may feel about 



