The frigate can sleep without interrupting her flight.

Does a bird that stays at sea for a long time actually sleep while flying? Watching his journey is not enough. Researchers have equipped large female Galpagpagos frigates with devices that record their brain activity, head movements, and movements. It was necessary to measure sleep, not infer it from their endurance.

The recordings revealed episodes of sleep during the hovering flight, mainly at night. Sometimes only one hemisphere slept, sometimes both. But these birds did not turn their journey into a long nap: they slept on average only about forty-two minutes a day in flight, against more than twelve hours daily on dry land.

This difference leaves a fascinating question: how do they maintain their performance with so little rest during their outings? Experience proves the presence of sleep in flight without solving all its mechanisms. It also makes it possible to distinguish two feats: sleeping without resting and supporting, during a trip, a very reduced amount of sleep.