soon ended, but the chuckle uttered occasionally by the bird when he is
not disturbed, or when, after uttering it once for some real cause, he
continues repeating it for no reason at all, producing the idea that he
has just made the discovery that it is quite a musical sound and that he
is repeating it, as if singing, just for pleasure. At such times the
long series of notes do not come forth with a rush; he begins
deliberately with a series of musical chirps uttered in a measured
manner, like those of a wood wren, the prelude to its song, the notes
coming faster and faster and swelling and running into the loud
chuckling performance. This performance, like the lost drake's call, was
repeated in the same deliberate or leisurely manner at intervals again
and again, until my curiosity was aroused and I went to the spot to get
a look at the bird who had turned his alarm sound into a song and
appeared to be very much taken with it. But there was no blackbird at
the spot, and no lost drake, and no bird, except a throstle sitting
motionless on the bush mound. This was the bird I had been listening to,
uttering not his own thrush melody, which he perhaps did not know at
all, but the sounds he had borrowed from two species so wide apart in
their character and language.

The astonishing thing in this case was that the bird never uttered a
note of his own original and exceedingly copious song; and I could only
suppose that he had never learned the thrush melody; that he had,
perhaps, been picked up as a fledgling and put in a cage, where he had
imitated the sounds he heard and liked best, and made them his song, and
that he had finally escaped or had been liberated.

The wild thrush, we know, does introduce certain imitations into his own
song, but the borrowed notes, or even phrases, are, as a rule, few, and
not always to be distinguished from his own.