76 EVOLUTION OF BIRD- SONG 



surroundings. Rennie could suggest no key to the 

 diversity of learning in captive birds, especially in 

 the nightingale, which will learn the notes of other 

 birds and retain them after it has heard its own 

 species " unless it be that, from want of other 

 amusement, it (the captive) listens more when it is 

 confined J;i (Domestic Habits of Birds, p. 278). 



Mr. Hudson raises his voice against what he 

 considers a pestilent delusion, namely, that all wild 

 animals exist in constant fear of an attack from 

 numerous enemies watching for an opportunity to 

 spring upon and destroy them. He says that the 

 truth is, that they are free from apprehension unless 

 in the actual presence of danger. " Suspicious at 

 times they may be but the emotion is so slight, 

 the action so almost automatic, that the singing-bird 

 will fly to another bush a dozen yards away and at 

 once resume his interrupted song ' : (Birds in a 

 Village, p. 8). The demeanour of wild birds seems 

 to me not to bear out this view. Except in the 

 season of love with many creatures a period of 

 indiscretion- -they are all keenly watchful for the 

 approach of enemies. Such birds as the woodpeckers 

 and titmice, when bark-searching, or others feeding 

 on open ground, are very persistent in diverting 

 their attention from their expected food, in order to 



