THE PLAY OF ANIMALS. 103 



is the reason for it. The same is true, as a rule, of the 

 cheerful hopping of birds from bough to bough and to 

 the ground. Courtship, too, is at the bottom of much of 

 the playful motion, as well as of voice practice. Re- 

 ferring this class to the next chapter, I here confine my- 

 self to a series of examples, most of which can be 

 attributed with certainty to purely play impulse, and 

 the remainder with great probability. First we notice 

 the learning to fly, swim, or walk by young birds. 



Birds can no more fly of themselves than babies can 

 walk. The infant's kicking corresponds to the flutter- 

 ing of little birds in the nest and his first step to its 

 first attempt at flight. The tiny creature is very timid, 

 and hardly dares to trust itself in the air. According to 

 Hermann Miiller's observation, a canary bird makes its 

 first attempt to climb up on the nest rim on about the 

 sixteenth day. Weinland gives a detailed account of a 

 canary family: " Sixteenth day, 8 a.m.: The young dare 

 not climb out of the nest, but reach and stretch a 

 great deal. 10 a. m.: Amid great tumult one fluttered 

 onto the rim of the nest and perched there, breathing 

 hard and fast, appearing to be frightened at his own 

 daring. In a minute the forward youngster is back in 

 the nest. Seventeenth day, 7 a.m.: The feet as yet serve 

 only as wide supports, like those of the ostrich, and not 

 for dexterously clinging to boughs, as will be their later 

 function. Twelve o'clock: Little Blackhead, the strong- 

 er one, has hopped out on the perch near the nest and 

 down on the floor of the cage, and from there through 

 the door of another cage, then quickly back. The little 

 feet are still very unsteady, especially on the perch. On 

 the ground he sometimes steadies himself with his tail, 

 a use which is not made of it in later life. Eighteenth 

 day: Both little ones have hopped about in the cage 

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