Except when nesting, swifts spend their lives in the air, living on the insects caught in flight; they drink, feed, and often mate and sleep on the wing.

Do chimney swifts sleep while flying?

Feeding “on the wing,” they capture flies, bugs, wasps, and other insects. Chimney Swifts spend more time flying than other species of birds. They copulate in flight, and drink and bathe in the rain while flying. They do stop flying to sit on eggs and to roost at night for sleep.

Do birds sleep while they're flying?

Migrating birds may also rely on USWS to rest. The long migration flights of many species don't allow for many chances to stop and rest. But a bird using USWS could both sleep and navigate at the same time. There is evidence that the Alpine Swift can fly non-stop for 200 days, sleeping while in flight!