STRUCTURE OF THE VOICE ORGAN 



generally attacked, and a well-known surgeon exhibited 

 some years since a preparation of a sheep so treated, in 

 which the bird had performed the operation of " colo- 

 tomy," or cutting into the large intestine. But it is 

 now certain that the kea actually prefers lean to fat, 

 like our old friend Jack Sprat, but, unlike that gentle- 

 man, will eat both substances. One might think 

 possibly that this change of feeding habits which may 

 ultimately be responsible for a change in at least the 

 digestive organs of subsequent keas, and be thus a most 

 excellent example of the influence of man upon faunas 

 having been acquired would be fixed, and that animal 

 food would now be a necessity. This, however, is not 

 so. Specimens at the Zoo have been fed on ordinary 

 parrot food, and have thriven thereon and showed 

 no symptoms of pining for unnatural mutton chops. 

 Nevertheless, mutton chops have often been freely sup- 

 plied to these birds when in the parrot house. The cap- 

 acity for an entire change of diet gives the philosopher 

 room " furiously to think,'' for it seems likely that many 

 kinds of beasts in the past have disappeared from the 

 face of nature through inability to adopt such liberal 

 opinions, and it is a fact that omnivorous creatures, 

 who need therefore place but little dependence upon the 

 vagaries of Nature, are often of primitive and long 

 existent kinds. This parrot, like others, has a voice. 

 Sir Walter Buller asserts that it mews like a cat, and 

 that it also utters a " whistle, a chuckle, and a sup- 

 pressed scream," a round of noises which is unsurpassed 

 in the bird tribe. This flexibility of voice (and it may 

 be added that the kea can be instructed in the art of the 

 usual parrot unpolite conversation) depends partly in 

 these birds upon the complicated structure of the voice 

 organ. That organ has several muscles pulling different 

 ways, and thus allowing of much change in the shape of 

 the air column, which causes the vocal chords to vibrate 



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