ON THE NOTES OF BIRDS. 43 
what is here advanced, I shall observe that I have 
known many instances of birds having nests after 
they have entirely ceased singing, and that some 
species, as the Wood-Lark, Redbreast, Wren, and Dip- 
per, sing long after they have done breeding. Caged 
birds also continue in song much longer than birds 
at large, though they have no mates to solace and 
amuse; and it is remarkable that almost any kind of 
shrill continued noise is sufficient to stimulate them 
to sing. That birds of the same species distinguish 
each other by their notes better than by any other 
circumstance, and that the songs of the males serve 
to direct the females where to seek their society, as 
Montagu has suggested, appears to me highly pro- 
bable ; but I must differ from this ingenious naturalist 
when he asserts that love is the sole cause of their 
songs*. In support of this opinion he states that 
the males of our Warblers, before they pair in spring, 
sing almost incessantly and with great vehemence, 
that from the time of pairing till the hens begin to sit 
they are neither so vociferous nor so frequently heard 
as before, that during the time of incubation their 
songs are again loud, but not so reiterated as at the 
first, and that so soon as the young are extruded 
from the eggs they cease singing entirelyf; but it 
* This he does, in effect, in the Introduction to the ‘ Ornitho- 
logical Dictionary,’ p. 28 and following. 
+ See the Introduction to the ‘ Ornithological Dictionary,’ 
pp. 30, 31. 
