Swoopy-birds

There's a flock of birds that live on the telegraph wires opposite us. Every now and again, they leave the wires and swoop around collectively in the air. It's quite a sight. An even better sight is when they dive-bomb the surface of the river — right outside the window.

Despite the internet, I'm not sure what they are, but this one's tail isn't that forked, although I was pretty certain I saw one with a swallow-like tail.