280 THE PLAY OF ANIMALS. 



I need not multiply these examples. Enough has 

 been said to show that birds invariably sing during 

 their mating time, but not exclusively then. The 

 blackcock, starling, and robin also sing out of this 

 season, as well as the water ouzel, which Tschudi has 

 so beautifully described, while the wren, red linnet, and 

 goldfinch can be heard all winter; the white-throat, too, 

 sings all the year round. Indeed, it may be that the 

 breeding time of some birds is variable, as seems to be 

 the case with the water ouzel, which, Tschudi says, "does 

 not confine itself to any particular month; the young 

 just hatched may be seen even in January." Besides, 

 birds sing not only before pairing but all through the 

 breeding time; in numberless cases the male pours out 

 his sweetest song while his mate is on the nest. This 

 is obviously play, rather than courtship. The duets * 

 that they sometimes produce together are probably the 

 effect of heredity; while in other cases the male song is 

 taken up by imitation on the part of the female. Hud- 

 son says that a singing female usually has plumage the 

 same as her mate.f Finally, there are rare cases where 

 the male sings better at other times than during his 

 courtship. Spencer, in his article " On the Origin of 

 Music," says this is true of the thrush. | And Hudson 

 says of a small yellow finch found in La Plata that in 

 August, when the trees are blooming, a flock of these 

 birds will appear in a plantation, perching on the boughs 

 and beginning a concert in chorus, " producing a great 



* Examples in Darwin's Descent of Man. chap. xii. 



f The Naturalist in La Plata, p. 283. 



X Mind, XV (ISnO). p. 452, Spencer sees in this fact a contra- 

 diction of Darwin's theory. I do not understand why, since it is 

 so probable that vocal reflexes in ,2:eneral are transmitted by hered- 

 ity, and so may always be called forth by other excitation. 



