264 FROM NORTH POLE TO EQUATOR. 



petulant expression to his own prejudice. A dispassionate observer 

 must soon perceive that a bird's song, though it remains essentially 

 the same, varies with every emotion, that it flows quietly on, ascends, 

 bursts out triumphantly, and dies away again, according to the pre- 

 vailing mood, and that it awakens an echo in the breast of other 

 males. If the view referred to were correct, each bird would sing 

 exactly like every other of the same species; it would pour forth its 

 appointed lay as mechanically as a musical box emits the tunes 

 plugged up in its rotating cylinder; none could change or improve 

 his song, or strive to surpass his fellows. Our own view is exactly 

 the opposite, for we are convinced that a bird sings with perfect 

 consciousness, that in his song he lays bare his soul. He is 

 a poet, who, within his own limits, invents, creates, and struggles 

 for utterance; and the motive throughout is love for the opposite 

 sex. Dominated by this love, the jay sings, whistles, and mur- 

 murs, the magpie chatters, the croaking raven transforms its rough 

 sounds into gentle, soft notes, the usually silent grebe lets its 

 voice be heard, the diver sings its wild yet tuneful ocean-song, the 

 bittern dips its bill under water that the only cry at its command 

 may become a dull, far-sounding booming. A bird does indeed sing 

 only at a certain season, but it is not because it cannot do so at 

 other times, but because it has then no inducement, no inclination 

 to sing. It is silent when it no longer loves; to speak more pro- 

 saically, when the pairing-time is past. This is clearly proved in 

 the case of the familiar cuckoo. Three-fourths of the year go by 

 and its call is not once heard; spring comes round in the revolution 

 of the seasons and it sounds forth almost incessantly from early 

 morning till late in the evening, as long as the pairing-time lasts. 

 But it is silent sooner in the south than in the north, sooner in the 

 plains than in the mountains, exactly corresponding to the brooding- 

 time of the foster-parents, which begin their nest-building earlier, 

 and finish the rearing of their young sooner in the south and in the 

 plains than in the north and in the highlands. 



During courtship many birds supplement their vocal eiforts by 

 pleasing movements, whether executed with the help of the wings 

 or of the feet; others by peculiar attitudes in which they display 



