THE PLAY OF ANIMALS. I95 



debted to Weinland's diary for the records of a family 

 of canaries. On May 14, 1861, the shells were broken. 

 One bird with a black head was the strongest and most 

 active of the brood. On June 2d little Black-head 

 sang for the first time, or rather he twittered while his 

 father sang. This is a good example of playful imi- 

 tation.* 



In Thiiringia chaffinches are bred that have a 

 specially acquired song, no one knows Avhy, probably 

 through unconscious selection. If young ones are 

 reared near those having the special song, they catch 

 the note in their play.f 



The many cases, too, where the female imperfectly 

 imitates the song of the male may be playful. Then 

 there is the well-known tendency of song birds to make 

 themselves heard when another is singing, when a piano 

 is being played, or conversation carried on. Imitation 

 here becomes rivalry. 



But imitation is not confined to singing in young 

 birds. " They are like little monkeys," says Hermann 

 Miiller; " example always excites them. When one little 

 one, whose wings are feathered or not, as the case may 

 be, begins to flutter, all the little wings are agitated." 

 This observation seems to prove that it is not individual 

 experience alone that causes a flock of grown birds to 

 take flight simultaneously.]; I have already pointed out 

 that young chickens take twice as long to learn to walk 

 alone as when tliey have the maternal exanqjle before 

 them, and that waterfowls go into the water with their 

 young and swim before them. Darwin says, in his 

 manuscript left unpublished: "It might have been 



* F. Weinland. Fine Vosrelfamilie, Der zoologische Garten, 1861. 

 f Nanmann, Nnturfresphichte der Vogel Deutschlands, iv, p. 27. 

 :}: Buchncr, Aus dem Geistesleben der Thiere, p. 30. 



