Why The Title?

The phrase is from Robert Penn Warren's poem Evening Hawk. The first 11 lines are:
From plane of light to plane, wings dipping through
Geometries and orchids that the sunset builds,
Out of the peak's black angularity of shadow, riding
The last tumultuous avalanche of
Light above pines and the guttural gorge,
The hawk comes.
His wing
Scythes down another day, his motion
Is that of the honed steel-edge, we hear
The crashless fall of stalks of Time.

The head of each stalk is heavy with the gold of our error.