How does that work then? After spending most of the day on the wing grabbing flying food, in much the same was as housemartins do, there seems to be a given signal and then all the swifts get together and fly down the row of houses in which ours is situated, often just skimming roof tops or screaming round the corners of walls. Literally screaming because that is their call when formation showing-off.
They are only here from about May to August. Guess that's when the insect population is highest. But some of them live for 15 years or so. That means some of the same ones are here as we met on arrival 14 years ago.
It's a great sight and sound though and one of the many I will miss. I intend to spend a lot of the evenings this summer on the patio, wine glass in hand, watching the swifts showing off.