Out of the dimming sky a speck appeared,
then another, and another.
It was the starlings going to roost. 
They gathered deep in the distance,  flock sifting into flock,
and strayed towards me, transparent and whirling, like smoke.
They seemed to unravel as they flew,
lengthening in curves, like a loosened skein. 
I didn’t move;
they flew directly over my head for half an hour. 

Each individual bird bobbed and knitted up and down
in the flight at apparent random, for no known reason except
that that’s how starlings fly, yet all remained perfectly spaced.
The flocks each tapered at either end from a rounded middle, like an eye.
Overhead I heard a sound of beaten air, like a million shook rugs, a muffled whuff.
Into the woods they sifted without shifting a twig,
right through the crowns of trees, intricate and rushing, like wind.

Could tiny birds be sifting through me right now,
birds winging through the gaps between my cells,
touching nothing, but quickening in my tissues, fleet?
~Annie Dillard from Pilgrim at Tinker Creek