People tend to dismiss them as "rats with wings" but when they fill the sky out of nowhere like this, a tornado of wing and tail, they're as beautiful as any other bird.
At evening, casual flocks of pigeons makeI think those pigeons only appear in dreams (or poetry). In my experience, there's very little undulation, ambiguous or otherwise. Mostly a lot of wild flapping.
Ambiguous undulations as they sink,
Downward to darkness, on extended wings.