They are composed of two sounds, both beautiful--the bright pure gushing robin-like note, and the more tender expressive swallow-like note.

And that is all; the song scarcely begins before it ends, or collapses; for in most cases the pure sweet opening strain is followed by a curious little farrago of gurgling and squeaking sounds, and little fragments of varied notes, often so low as to be audible only at a few yards' distance.

It is curious that these slight fragments of notes at the end vary in different individuals, in strength and character and in number, from a single faintest squeal to half a dozen or a dozen distinct sounds.

In all cases they are emitted with apparent effort, as if the bird strained its pipe in the vain attempt to continue the song.
The statement that the redstart is a mimic is to be met with in many books about birds.

I rather think that in jerking out these various little broken notes which end its strain, whether he only squeaks or succeeds in producing a pure sound, he is striving to recover his own lost song rather than to imitate the songs of other birds.
So much entertainment did I find at that spot, so grateful did it seem in its openness after long confinement in the lower thickly wooded country, that I practically spent the day there.