Looking for a Sunset Bird in Winter

The west was getting out of gold,
The breath of air had died of cold,
When shoeing home across the white,
I thought I saw a bird alight.

In summer when I passed the place
I had to stop and lift my face;
A bird with an angelic gift
Was singing in it sweet and swift.

No bird was singing in it now.
A single leaf was on a bough,
And that was all there was to see
In going twice around the tree.

From my advantage on a hill
I judged that such a crystal chill
Was only adding frost to snow
As gilt to gold that wouldn't show.

A brush had left a crooked stroke
Of what was either cloud or smoke
From north to south across the blue;
A piercing little star was through.