270 VOICES OF BIRDS. 



produced by no exertion, or occasioning no lassi- 

 tude in muscle, or relaxation of the parts of action. 

 In certain seasons and weather, the nightingale 

 sings all day, and most part of the night ; and we 

 never observe that the powers of song are weaker, 

 or that the notes become harsh and untunable, 

 after all these hours of practice. The song-thrush, 

 in a mild, moist April, will commence his tune 

 early in the morning, pipe unceasingly through 

 the day, yet, at the close of eve, when he retires 

 to rest, there is no obvious decay of his musical 

 powers, or any sensible effort required to continue 

 his harmony to the last. Birds of one species sing 

 in general very like each other, with different degrees 

 of execution. Some counties may produce finer 

 songsters, but without great variation in the notes. 

 In the thrush, however, it is remarkable, that there 

 seems to be no regular notes, each individual piping 

 a voluntary of his own. Their voices may always 

 be distinguished amid the choristers of the copse, 

 yet some one performer will more particularly en- 

 gage attention by a peculiar modulation or tune ; 

 and should several stations of these birds be visited 

 in the same morning, few or none probably will be 

 found to preserve the same round of notes ; what- 

 ever is uttered seeming the effusion of the moment. 

 At times a strain will break out perfectly unlike 

 any preceding utterance, and we may wait a long 

 time without noticing any repetition of it. During 

 one spring, an individual song-thrush frequenting 

 a favourite copse, after a certain round of tune, 



