There is a river flowing across the sky.
A narrow band of specks moving in fluid motion - fast and irresistible.
There must be thousands of individual life forms that make up what seems like one superorganism.
It flows ceaselessly. Its very continuation generating surprise in every moment that passes.
New groups join in a flash of dark sky from the top of the trees, as they take off and swerve into the current.
And then suddenly another swarm is upon us - right above our heads - catching us unawares as they emerged from the sky behind us.
The noise is extraordinary. If strength had a signature sound this might be it. Not show-ful, but impressive nonetheless. It is a modest and incidental expression of power.
This murmuration of starlings is close enough for us to make out the individuals as they pass low over our heads. Each one flaps their wings a few rapid beats, then glides with wings withdrawn - in a manner that draws to mind the motion of a seal through water -before beating once again.
The last of that group is passes us and a palpable vacancy is left in the air.
Silence returns to the marsh in the twilight.
Silence save for a few ducks and a coot on the water in front of us.
As we scan the horizon again we see a dozen or more small groups in the distance all heading onward passed us and to their roost in the east. It is a great gathering of the clans. The very meaning of safety in numbers.
It feels as if we are in the midst of something rare and meaningful. There is a sense of purpose to the murmurations. A message has got out that we were not privy to. We are mere bystanders.
Some groups hold a steady shape. Others a steady line. Still others weave left and right, or stretch and contract, or spread and compress.
In the field to our left, a ribbon of starlings appears against the white cloud. At the moment that our eyes find them, something triggers a ripple through their ranks. They dance a wave into their ribbon like the pulse of a heartbeat on a monitor. Then again; and again.
The light is fading fast now, and it seems all parties have completed their journey. The performance on this great stage has finished for the day.
The wait had been worth it. We had watched the sunset over the hills beyond the reedbeds before the main act arrived. The sky transitioned from golden yellow to deep, deep blue as we watched in awe.
Now the show has ended, a narrow crescent moon shines down from on high.