Tern flock?

Smokey Bear

At Geary and Fillmore a few minutes ago (12/1/2020; 08:20), a bright flock of large, white, swift-moving birds moved over Pacific Heights, maybe visible from Lafayette Square if you were looking south. I was too slow getting the binocs out of the bag for more than a few seconds’ view. I’m presuming these were Elegant Terns.

Anyone missing a flock of terns?