With One White Wing

Elizabeth Spires' With One White Wing is an unusual poetry book -- each of the poems is a riddle.

Here's an example:
I weigh less than a feather
but you can't pick me up.
I can dance but I can't sing.
Without you, I am nothing.

With One White Wing by Elizabeth Spires is out of print,
but you can find it in your library or find used copies on A1 Books .

Do you know the answer to the poem-riddle above?
It's a shadow!