Migrating Birds take Powernaps
Many people find that taking a fifteen minute powernap during the day can help improve their productivity and maintain their energy level. As it turns out, animals also use powernaps to keep them on their migratory schedule.
A recent study published in the journal Animal Behavior found that birds take hundreds of powernaps all day long, each one lasting an average of just nine seconds. This information helps explain the mystery of how birds are able to fly for many long hours during their migration with little time for rest.
The team of scientists from the Bowling Green State University in Ohio studied Swainson's thrushes, which fly up to 3,000 miles from Canada and Alaska to Central and South America each autumn, only to return north in the spring. The birds fly mostly at night and rest during the day. Scientists observed caged thrushes for a year and recorded their sleep patterns and found that during their migratory seasons, they reverse their sleep patterns to stay awake at night.
The thrushes were found to take two types of powernaps, which the scientists termed "unilateral eye closure," during which the birds rest one eye and one half of their brain while the opposite eye and side of the brain remain awake and alert; and "drowsiness," in which the eyes are partially shut but some visual processing is still performed.
If you co-sleep with your baby, this type of semi-consciousness may sound very familiar to you. Many new mothers claim they remain completely aware of their surroundings when they are sleeping with their child nearby. These mothers say that, particularly while co-sleeping, they can sense the child's presence and hear any noises that might alert them to a problem. While they are able to get some sleep, their senses remain awake all night.
Similarly, the thrushes' powernaps allow the birds to remain aware enough to sense potential danger, yet still get the rest they need.
"I think what's interesting about our findings is that even animals that should be highly adapted to sleep loss cannot go on indefinitely," said study team member Thomas Fuchs. "That a need for sleep cannot be eliminated even in these species underscores the importance of sleep for many, if not all, animals."