Scientists prove birds can sleep while flying

For the first time, researchers have found that birds can sleep in flight without colliding with obstacles or falling from the sky.

Together with an international team of colleagues, Niels Rattenborg from the Max Planck Institute in Germany measured the brain activity of frigate birds and found that they sleep in flight with either one cerebral hemisphere at a time or both hemispheres simultaneously.

Despite being able to engage in all types of sleep in flight, the birds slept less than an hour a day, a mere fraction of the time spent sleeping on land.

It is known that some swifts, songbirds, sandpipers, and seabirds fly non-stop for several days, weeks, or months as they traverse the globe, researchers said.

Given the adverse effect sleep loss has on performance, it is commonly assumed that these birds must fulfil their daily need for sleep on the wing, they said. Researchers analysed how birds may sleep in flight without colliding with obstacles or falling from the sky.

One way they do this may be to only switch off half of the brain at a time, as Rattenborg showed in mallard ducks sleeping in a dangerous situation on land. The findings were published in the journal Nature Communications.