There are a huge number of signs in the world that help predict future events in the behavior of living organisms. Swallows were no exception. People say: "Swallows fly low - towards the rain." Is there a scientific basis for this belief?
Too romantic natures may argue that swallows are extraordinary birds, endowed with a special flair and intuition, they are able to sense changes in the weather and warn about it with their behavior.
However, everything is much simpler. It is enough to turn to the school physics course and recall the law of universal gravitation (F = mg) to explain the behavior of swallows before the rain begins.
Swallows are birds of prey that feed themselves and feed their chicks with the smallest insects and midges that live in abundance in the air and are not always visible to the naked eye.
Shortly before it starts to rain, the humidity rises significantly. As a result, tiny drops of water settle on the wings of insects. This leads not only to an increase in the weight of the wings, but also to an increase in the body weight of the insect itself, the activity of which, accordingly, decreases. Midges, bugs, etc. forced to fly lower than usual. Therefore, their pursuers - swallows - descend in their flight closer to the surface of the earth.
A person who is not able to see the true reason for such a flight of birds ascribes unusual abilities and capabilities to swallows.
But not only the approaching rain can "force" the swallows to change their usual flight altitude. Sudden changes in temperature, such as an evening cold snap, lead to the same effect. And again, the reason lies in the changing, lower flight of insects. Therefore, virtuoso, exciting "dances" of swallows in the evening sky are not always the harbingers of bad weather.
The growing generation of these beautiful birds often "rejects" the habitual sign. And even during a light rain, you can observe frolicking swallows high in the sky. The fact is that the "youngsters", unencumbered by the prey of food, are practicing a new skill for them - flight.
