These struggles are accompanied with violent screaming. In early August when the first swifts are migrating south, strangers may be found roosting within a colony. None stay longer than a single night and it appears these strangers merely join resident swifts to pass the night. Migrating swifts have also been reported settling at dusk on telegraph poles. Like flying anchors, these symbols of high summer have greater mastery of the air than any other bird.
Swifts drink, bathe, preen, collect food and nesting material all without alighting.
The night is spent on the wing and they are the only bird known to mate on the wing. Once their young can fly swifts have no reason to linger here. Indeed, there seems no need for young birds to strengthen wings in practice flights. Parent swifts returning with food for their young reveal a large bulge below the beak due to a mass of insects packed into the throat pouch glued together in saliva. Detailed observations have shown that a swift may bring 40 meals a day to the young.