Some can also sleep through one eye open, as half of their brain is alert when the other is asleep. This is referred to as unihemispheric slow-wave sleep (USWS) and also it allows the resting bird to spring into activity quickly from rest if a threat philosophies while still gift able come satisfactorily rest if no threat arises. Ducks and waterfowl space particularly good at this, though other smashville247.net such as Peregrine Falcons and also Eurasian Blacksmashville247.net deserve to do this as well. Varieties that usage this adaptation might even have the ability to sleep while flying!
Migrating bird may likewise rely top top USWS to rest. The lengthy migration flights the many species don’t enable for countless chances come stop and rest.
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But a bird making use of 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!