THE LANGUAGE OF ^IRDS. 
27 
the summer excitements, monitions, informations, are 
not needed in autumn, and the notes conveying such 
intelligences are no longer heard. The periodical 
calls of animals, croaking of frogs, &c., afford the 
same reasons for concluding that the sound of their 
voices, by elevation, depression, or modulation, con- 
veys intelligence equivalent to an uttered sentence. 
The voices of birds seem applicable, in most instances, 
to the immediate necessities of their condition ; such 
as the sexual call, the invitation to unite when dis- 
persed, the moan of danger, the shriek of alarm, the 
notice of food. But there are other notes, the designs 
and motives of which are not so obvious. One sex 
only is gifted with the power of singing, — for the 
purpose, as BufFon supposed, of cheering his mate 
during the period of incubation ; but this idea, gal- 
lant as it is, has such slight foundation in probability, 
that it needs no confutation ; and after all, perhaps, 
we must conclude that, listened to, admired, and 
pleasing as the voices of many birds are, either for 
their intrinsic melody or from association, we are 
uncertain what they express, or the object of their 
song. The singing of most birds seems entirely a 
spontaneous effusion, produced by no exertion, or 
