ON THE SINGING OF BIRDS. 34.3 



which might be supposed to contribute to 

 singing. 



Mr. Hunter found the muscles of the larynx 

 to be stronger in the nightingale than in any 

 other bird of the same size ; and in all those 

 instances (where he dissected both cock and 

 hen) that the same muscles were stronger in 

 the cock. 



I sent the cock and hen rook, in order to see 

 whether there would be the same difference in 

 the cock and hen of a species which did not 

 sing at all. Mr. Hunter', however, told me, 

 that he had not attended so much to their com- 

 parative organs of voice, as in the other kinds ; 

 but that, to the best of his recollection, there 

 was no difference at all. 



Strength, however, in these muscles, seems 

 not to be the only requisite; the birds must 

 have also great plenty of food, which seems to 

 be proved sufficiently by birds in a cage sing- 

 ing the greatest part of the year,* when the 

 wild ones do not (as I observed before) continue 

 in song above ten weeks. 



* Fish also which are supplied with a constant succession of 

 palatable food, continue in season throughout the greatest part 

 of the year ; trouts, therefore, when confined in a stew and fed 

 with minnows, are almost at all seasons of a good flavour, and 

 are red when dressed. 



