I've heard of murmuration, but I've thought it was only associated with starling. Last January while I was on my way to St. Louis I witnessed this strange event.
The birds appeared to be some sort of water fowl. We saw them sort of swarm near a creek.
Then they would break off in sections and cross the highway.
Then they would birds would break up into small groups. Some of the groups would head back to the creek. While the rest thinned out into v-shaped strains.
Eventually they all took a v-formation and headed southeast.
They streaked and floated across the sky in such a way that they reminded me of ink swirling through a glass of water.