ON THE NOTES OF BIRDS. 29 
mens. The Wood-Wren, Yellow Wren, and Lesser 
Pettychaps, for example, so much resemble each 
other, that even nice observers might have some dif- 
ficulty in determining them by inspection; and ac- 
cordingly we find that they have been a source of 
confusion, perplexity, and error among writers on 
ornithology ; as their notes, however, are. perfectly 
distinct, a little attention to them is sufficient to re- 
move every difficulty. In the same manner the Crow 
may readily be distinguished from the Rook, the 
Raven from both, and the males of most species from 
the females. 
The arrival of many of the Periodical Warblers is 
frequently first announced by their songs; and the 
clamorous night-calls of the Redwing and Fieldfare, 
in the months of October and November, serve to 
establish the fact that these birds migrate, and that 
they perform their journeys in the night. 
But these are not the only advantages to be de- 
rived from an acquaintance with the notes of birds. 
As the feathered tribes communicate their sensations 
and intentions to one another through the medium of 
modulated sounds, the proficient in what, without 
any impropriety, may be termed their language, can 
comprehend their various wants and emotions, and 
can participate in all their little joys and sorrows, 
hopes and fears. To him the music of the groves is 
not a confusion of pleasing tones merely, but the 
melodious interchange of thought and feeling, which, 
