A Way to Know

I know that winter is at hand

When a bird of mountain blood

Whirls her wing and skims to earth

With song of minor solitude -

A duple note, a two-way tremble

Of music in the sun:

And though she sits in roses,

I know that summer's done.

Down slope and crust of lustre,

Loaded with light snow,

Winter slides upon us

And a bird told me so.