Swallows in flight are very difficult to photograph - you nailed it.
Brent, you are the surfing photo master.
Screw the kids, buy the lens.
Gorgeous photos, tack sharp; no noise. I've been after a pair in my area but have not been able to get photos like yours.
Canon 90D 100-400mm L II, 1/1600, F10, ISO 320
What has she done to her eyebrows.