Why do some Birds Sing ? 249 



which heads this article. In the beginning of biid- 

 life there were few, if any, songsters. The birds' 

 immediate ancestors made day or night hideous if 

 they cried out at all, and only after countless cen- 

 turies of gradual evolution of highly-specialized 

 forms did the song-bird, as we know it, come upon 

 the scene. These early musicians possibly sang 

 only during the nesting season, and more to please 

 their mates than themselves. The original impulse 

 still survives ; but there is now an added phase, — 

 singing from pure love of music. I have men- 

 tioned several instances of this, and many more 

 could be given, but with one of a striking char- 

 acter I will conclude. It is well known that in 

 autumn there is comparative silence among those 

 birds that in early summer made the woods and 

 fields fairly tremble with the flood of song, and in 

 autumn those birds that are migrating southward 

 seldom utter more than an occasional chirp. 

 Among all these an exception to the rule some- 

 times happens. As if some object near recalled 

 happy by-gone days, the almost silent bird pauses 

 in his occupation and sings as though it were 

 May-day and not October. This is not so unusual 



