ON THE SINGING OF BIRDS. 
to this is, that the origin of the notes of birds, 
together with its gradual progress, is as difficult 
to be traced, as that of the different languages 
in nations. 
The loss of the parent cock at the critical 
time for instruction hath undoubtedly produced 
those varieties, which I have before observed 
are in the song of each species; because then 
the nestling hath either attended to the song of 
some other birds; or perhaps invented some | 
new notes of its own, which are afterwards per- 
petuated from generation to generation, till simi- 
Jar accidents produce other alterations. . The 
organs of some birds also are probably so defec- 
tive, that they cannot imitate properly the pa- 
rental notes, as some) men can never articulate 
as they should do. Such defects in the parent 
bird must again occasion varieties, because these 
defects will be continued to their descendants, 
who (as I before have proved) will only, attend 
to the parental song. Some of these descend- 
ants also may have imperfect organs; which 
-will again multiply varieties in the song... - 
The truth is, as I have already observed, that 
scarcely any two birds of the same species have 
exactly the same notes, if any are\accurately 
attended to, though there is a general resem- 
blance. | 
