They always look graceful when frozen by the camera in mid-flight. At a market, I saw a shopkeeper throwing grains and the birds swooping in from a telephone wire.
Pays to keep the camera in S or shutter priority mode for street photography. I rolled the dedicated shutter speed control dial rapidly while lifting the camera to my eye.
It all happened in a matter of a few of seconds. Before I hit the targeted 1/4000th of a second, the birds were already overhead.
While I can control the camera, the flight formation is all luck. I added the green hue in post.
Sony Alpha a7R, ISO 200, f4, 1/3200 sec.