IvANGUAGE OF BIRDS 



conveying one particular idea. Fear and anger 

 are the two dominant emotions in all wild life. 

 Pure gladness of heart probably comes next ; 

 then come the ideas of love, of welcome, of warning, 

 and of numberless finer feelings, all of which are 

 set forth in a minor key. Something of the 

 evolution of language may be seen when we 

 consider the lower orders of Nature. Fishes 

 are practically dumb ; reptiles express little be- 

 yond anger and fear, and these only by a not 

 largely modulated hiss, to which their fellows 

 accord little, if any, sign of recognition. The 

 only animals outside the avian class that may be 

 said to attempt any sort of song are frogs and 

 certain eccentric house-mice. In mammals, the 

 use of sound is comparatively limited, although 

 dogs can set forth plainly anger, fear, pain, and 

 welcome by modifying the intonations of their 

 bark. In birds, on the other hand, we can 

 follow with ease a wide range of ideas expressed 

 with certainty and force. The fierce scream of 

 eagle or hawk, the hissing of geese, the indignant 

 cry of tern or skua gull when their haunts are 

 invaded, all express anger. The sound indicating 

 fear, although often blended with that of anger, 

 may still be clearly distinguished. Let one 

 listen attentively to a horde of sparrows fighting, 

 and he may readily detect the clear ringing note 

 of rage and victory as compared with the weaker 

 and more tremulous twitter of fear and defeat. 

 The note of warning, too, has a peculiar intona- 

 tion of its own which is plainly known and ac- 

 knowledged by all the members of the species. 

 The sharp, rapid cries of swallow and martin when 

 a hawk swoops down upon them can bear one 

 interpretation only, " Look out, the enemy is 

 upon us." But all these are expressive of the 

 cruder emotions merely : as in human speech, 



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