312 Observations on the 
that the calls of birds, at least, are innate; 
and that, at this early age, ten days are not 
sufficient to enable nestlings to acquire even 
the calls of those under which they are bred; 
thus, clearly establishing the validity of the 
first experiment made with the young green 
grosbeaks. Shortly after, the redbreast be- 
gan to record ;* but in so low a tone, that it 
was scarcely possible to trace the rudiments 
of its future song in these early attempts: as 
it gained strength and confidence, however, 
its native notes became very apparent; and 
they continued to improve in tone, till the 
termination of July, when it commenced 
moulting; which did not, as was expected, 
put a stop to itsrecording.t About the mid- 
dle of August it was in deep moult, and by 
the beginning of October had acquired most 
of its new feathers. It now began to ex- 
ecute its song in a manner calculated to re- 
move every doubt as to its being that of the 
* The first endeavours of a young bird to sing are termed recording. 
+ The important operation of moulting undoubtedly affects the sing- 
ing of wild birds very considerably ; and may, perhaps, be a principal 
cause of their silence inthe month of August. The London birdeatchers 
are well aware of the advantages of occasioning their call-birds to moult 
prematurely, which, by this means, are brought into full song, while 
other birds are nearly mute. For an account of the manner in which 
this is effected, see Pennant’s British Zoology. Vol, I, p. 332. 
