You have often seen a picture when a bird slept on a branch or wire without any hesitation and did not fall. Surely, surprise or even amazement has arisen in you more than once, how she does it.
In nature, almost every animal takes such a position before going to bed, in which you can relax the maximum number of muscles. After all, sleep is primarily considered a rest for the body and for them too. However, most birds are not happy with this state of affairs. They can only sleep when the muscles in their paws are tense.
The fact is that in birds, tendons connect the leg muscles and fingers. It turns out when the bird lands, muscles contract, tendons stretch, and fingers flex. During sleep, the bird does not move, so it cannot straighten its legs. As a result, she does not let go of her support. When the bird comes to a state of wakefulness, it rises, and the fingers release the place of recent hibernation.
Birds that sleep in water often only stand on one leg. It is not difficult to give an explanation for this. This way they lose less heat and keep the required body temperature. For example, long-legged herons and flamingos resort to a similar sleeping technique.
However, there are birds that are good at snoozing on the fly. For example, storks take turns sleeping without trouble during their long flights. The dark tern has been able to fly over the sea for more than one year, and without stopping for breaks.
