A clever little bird who “knows” geometry.

Often I approached the window of the apartment located on the eleventh floor, just to check the wind direction and visually assess the weather. And I drew attention to the REGULAR strange behavior of sparrows, which, like all other birds, I have been carefully feeding for several decades of years.

The picture is as follows: Sparrows fly onto the ledges of the building at the third floor level. After sitting there for a couple of seconds, they take off two, three, or even four floors higher. Again, a short rest, and again a flight up. Having gained height at the level of the last floors of our nineteen-story building, they rest there for half a minute or a minute, then a rapid, free fall jump down a steep parabola, which, close to its top, turns into a flight almost parallel to the surface of the earth, landing on top of some tree. And this is NOT a single, out-of-the-ordinary case, but rather frequent “sky-diving without opening a parachute,” which birds have in their wings.

Birds of prey, of course, they fall to their chosen prey from a height, with their claws outstretched.

But why would sparrows do that?

A few assumptions.

Perhaps it is much more convenient for them to see a flying fly from above than from below, the sky shining with bright blue, when viewed from below, blinds and does not allow them to see the fly. And from above, against the background of relatively dark soil, the shiny wings of a fly reflecting sunlight immediately catch the eye.

Another assumption is that their nest is located somewhere near the top of a tree and it is easier to reach it from above than by breaking through branches and dense foliage from below.

I think the second assumption is closer to the truth – having picked up some food on the ground, they first, holding it in their beak, climb higher, and then fly in a steep dive to the nest.

The most noticeable thing about their behavior is their persistent regularity in performing this aerobatics! Many times in an hour!

Interestingly, I’ve never noticed this in pigeons. Pigeons are stronger birds and incomparably better flyers than tiny sparrows.

And they need to be fed less often – the smaller a living being is, the greater its body surface area to volume ratio, which means that for warm-blooded creatures, heat loss is greater. Therefore, the smallest mammal, the shrew, weighing only two grams, must eat almost continuously to ensure its existence.

I once touched on this topic, analyzing the gross mistake of scientists of Lilliputia, who believed that since Gulliver is twelve times larger than Lilliputians, then he should eat 1728 times more food than an ordinary Lilliput.

The same surface-to-volume ratio is important for actinouranium 235. It is NOT the “critical mass” that should be a factor determining the “explosive” ability of uranium or plutonium, but rather the CRITICAL surface-to-volume RATIO. If the thinnest film of uranium is rolled out over tens of square kilometers, its mass can be tons and tens of tons, but no explosion will occur, because the “leakage of free fast neutrons” will be so great that there can be no avalanche-like reaction (and not a “chain”). So there will be no explosion.

And the sparrows are anyway clever birds!

20 VII 2025