Scientists have shown that birds can sleep in flight – BBC

An international team of scientists led by researchers from the Institute of Ornithology of the Max Planck Society (Germany) found the answer to the question for decades haunted the researchers. And the question is simple: can the birds sleep during flight

Can – proved by scientists, after spending most unusual study, to follow the order of the day birds for hours in the air

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it is well known that some species of swifts, warblers , Bekasovo and seabirds can make non-stop flights duration in days, weeks, and more. Considering the negative consequences resulting animals lack of sleep, many scientists believed that the birds somehow manage to sleep during the flight. However, it was recently shown that some birds are really able to stay awake for weeks, minimizing the time of sleep, and it’s even more added confusion to the issue of sleep possibility in the air

The main problem in the answer to this question -. Lack of research brain birds during flight, which could shed light on this problem. Like a bird can sleep in the air, without encountering relatives and without falling down? According to one version, the birds are not completely asleep, but in separate hemispheres, first left, then right. There are reports showing that this is the sleeping mallard, if there is a danger on land. These birds, if they are on the edge of the pack, always awake one hemisphere of the brain, and the corresponding eye is always directed towards the possible threats. Whatever it was, to secure sleep, scientists need to measure the electrical activity of the brain, and it requires the placement of color bird special devices

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in order to solve the problem, researchers needed to identify the moments when the bird is awake, and when you fall into one of the two known types of sleep – REM sleep (slow Wave sleep, SWS) and REM sleep (Rapid Eye Movement, REM). To do this, Niels Rattenborg, author of the work, together with Alexei Vysotsky University of Zurich have developed a miniature device,

removing bird brain EEG and the locking movements of the head during the flight.

Learn decided large frigates nesting in the Galapagos islands. It is known that these birds spend the whole week over the ocean in search of fish that chase predators to the surface. Birds placed with their heads devices sometimes flew for 10 days, for which flew up to 3 thousand. Km. All this time, the unit recorded EEG in both hemispheres of birds, head movement, the route and altitude using the GPS receiver. Upon returning to the birds began filming devices and the data processing. “Like many other animals in the Galapagos, frigates were pretty calm and continued to sleep, when I approached him a second time,” – he said co-author Bryson Voirin

The data analysis showed that the birds really sleep in. flight, but sleep is supposed to be so in an unusual way. During the day they are awake, engaged in the search for food. After sunset, the usual encephalogram switches into slow-wave sleep mode, and the bird hovered for several minutes. The scientists noted that at this time can be switched off as one, and the two hemispheres of the brain.

This means that the birds do not have to stay awake one hemisphere to retain control over aerodynamics flight.

However, another discovery was made by comparing the movements of the head EEG recordings hemispheres. When the bird soars in circles in the updraft, awake hemisphere of the brain responsible for the eye that looks into the turn, while the other sleeps, from which it follows that the bird keeps track of where to fly. “Frigates can watch the birds in order to avoid a collision, just as the duck track predators” – said Rattenborg

In addition, the periods of REM sleep is sometimes interrupted by short, just a few seconds of REM sleep phases. the researchers found. Unlike mammals, in which REM sleep lasts long and is accompanied by a complete relaxation of the muscles in birds it turns on for a few seconds. In contrast to the animals, the birds in this phase of sleep, though dropping at the time of the head, but can continue to stand on one leg.

Similarly, the frigates at the time of REM sleep for the duration of nod head, but their mission remains unchanged.

Perhaps the most important discovery for the scientists was the total sleep time: it turned out that during the day the birds allow themselves to sleep only 42 minutes. But, returning to the nest, they can sleep off and sleep for half a day. “Why are they so little sleep at night, if you hunt a little, remains a mystery,” – said Rattenborg. In the future, scientists are going to explain how bird so long without sleep. “Why do we and many other animals suffer from lack of sleep, while some birds perfectly adapted, it remains a mystery,” – he added. The work of scientists published in the journal Nature Communications .