THE SONG AND NOTES OF BIRDS. 101 



autumn, or, what is more correct, the young birds, 

 and a very large percentage of these autumn and 

 winter singers is composed of individuals reared 

 during the previous spring and summer. Thus, 

 then, we find that the autumn song of birds is 

 inspired by sexual passion after all. The old birds 

 commence to sing later in the season, and continue 

 the concert through the winter until the breeding 

 season, which often commences in favourable years 

 as early as the beginning of February. Not only so, 

 but as the season of reproduction approaches, the 

 music becomes more excited, more prolonged, louder 

 and perceptibly more energetic, as though the 

 singers were urged to greater effort by the quicken- 

 ing sexual instincts within them. 



It has been suggested, in a very recent work on 

 Natural History, that certain birds of high musical 

 powers at other times gradually lose their song or 

 suffer it greatly to deteriorate during the breeding 

 season, and our own Robin is given as an instance. 

 I have already explained the meaning of this, but I 

 should like to give another and perhaps still more 

 striking instance of a species losing its song in the 

 nesting season. This is the Missel-Thrush, a bird 

 that sings rapturously during the late autumn and 

 winter months, but drops his lay entirely by the 



