Do birds need to catch up on lost sleep?
We all know the feeling of needing to catch up on missed sleep, and it’s easy to imagine that other animals must also feel tired after a disturbed night. Indeed, some studies have shown that, like us, birds sleep longer and more deeply after being kept up. But, unlike us, there seem to be certain times of year when they can do without sleep.
One phenomenon has been called ‘migratory sleeplessness’, where birds seem naturally to reduce their need for sleep during the migration period. Throughout most of the year, North American white-crowned sparrows need to catch up on even small amounts of lost sleep, but during migration they reduce their sleep by up to two-thirds, with no apparent impact on their problemsolving skills. Another study looked at barnacle geese – they need to catch up on lost sleep in summer, but not in winter.