THE BIRD’S LANGUAGE 45 
more, not one of the sounds he utters is like 
those made by any other bird. If you know 
him well, whatever noise he makes, you will 
know at once that it is a robin. 
But there is something still more curious 
about it. No robin sings exactly like another 
robin. When you come to know one bird well, 
you can tell his song from any other bird’s. Of 
course, all robins sing enough alike for one to 
know that it is a robin song, but if you listen 
closely, you will see that it is really different 
from all others. 
Persons who have kept birds in cages have 
noticed the same thing. 
There is still another pomt to know. One 
bird does not always sing the same song. [| 
have heard a song sparrow sing’ five or six differ- 
ent songs, standing all the time in plain sight on 
a fence. In the same way I have known a mea- 
dowlark to make six changes in his few notes. 
Besides their own natural songs, many birds 
like to copy the notes of others. Our mocking- 
bird is very fond of learning new things, and he 
does not always choose songs either. 
He will imitate the noise of filing a saw, or the 
pop of a cork, as readily as the sweetest song. 
I have heard one sing the canary’s song better 
than the canary himself. 
