NESTLING HUMMING-BIRDS. 153 



broad bills, and wide gape, are essential to their mode 

 of life. The humming-birds, on the other hand, are 

 floral insect-hunters, and for this purpose their peculiarly 

 long bills and extensile tongues are especially adapted ; 

 while they are at the same time honey-suckers, and 

 for this purpose have acquired the tubular tongue. The 

 formation of such a tubular tongue out of one of the 

 ordinary kind is easily conceivable, as it only requires 

 to be lengthened, and the two laminae of which it is 

 composed curled in at the sides ; and these changes it 

 probably goes through in the young birds. 



When on the Amazon I once had a nest brought me con- 

 taining two little unfledged humming-birds, apparently 

 not long hatched. Their beaks were not at all like 

 those of their parents, but short, triangular, and broad 

 at the base ; just the form of the beak of a swallow 

 or swift slightly lengthened. Thinking (erroneously) 

 that the young birds were fed by their parents on 

 honey, I tried to feed them with a syrup made of honey 

 and water, but though they kept their mouths constantly 

 open as if ravenously hungry, they would not swallow 

 the liquid, but threw it out again and sometimes nearly 

 choked themselves in the effort. At length I caught 

 some minute flies, and on dropping one of these into 

 the open mouth it instantly closed, the fly was gulped 

 down and the mouth opened again for more ; and each 

 took in this way fifteen or twenty little flies in succession 

 before it was satisfied. They lived thus three or four 

 days, but required more constant care than I could give 

 them. These little birds were in the "swift" stage; 

 they were pure insect-eaters, with a bill and mouth 

 adapted for in sect -eating only. At that time I was not 



