ON THE SINGING OF BIRDS. 
I shall now proceed to state some general prin- 
ciples with regard to the singing of birds, which 
seem to result from the experiments I have 
been making for several years, and under a 
great variety of circumstances. 
Notes in birds are no more innate, than lan- 
guage is in man, and depend entirely upon the 
master under which they are bred, as far as 
their organs will enable them to imitate the 
sounds which they have frequent opportunities 
of hearing. 
Most of the experiments I have made on this 
subject have been tried with cock linnets, which 
were fledged and nearly able to leave their nest, 
on account not only of this bird’s docility, and 
great powers of imitation, but because the cock 
is easily distinguished from the hen at that 
early period, by the superior whiteness in the 
wing.* 
In many other sorts of singing birds the male 
is not at the age of three weeks so certainly 
known from the female; and if the pupil turns 
out to be a hen, 
<* ibi omnis 
«¢ Effusus labor.” 

* The white reaches almost to the shaft of the quil feathers, 
and in the hen does not exceed more than half of that space: it 
is also of a brighter hue. 
331 
