flocks, a drunken fingerprint

As if a cast of grain leapt back to the hand,
A landscapeful of small black birds, intent
On the far south, convene at some command
At once in the middle of the air, at once are gone
With headlong and unanimous consent
From the pale trees and fields they settled on.

What is an individual thing? They roll
Like a drunken fingerprint across the sky!

Richard Wilbur, "The Event"