In one of the villages of the Polessky district of the Kyiv region, little swallows hatched a week and a half ago. And although their parents actively feed them, concern arose: whether such a late autumn brood will be able to mature enough to fly away for the winter. After all, autumn has already arrived, the number of birds in Ukraine has decreased significantly and swallows are about to leave for warmer climes. “VoiceUA” addressed its questions to the head of the Bird Ringing Center of the I.I. Shmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine, Anatoly Poluda.
Mr. Poluda, we are used to birds hatching their chicks at the beginning of summer. Is such a late hatch normal or an anomaly?
The fact is that the swallows are already flying away. In particular, the shore swallow, which settles along the banks of rivers, has already flown away for the winter. Apparently, this is your barn swallow, which flies away around October 1st. But it happens that the migration process continues until October 20. Therefore, they have another month of reserve, there is still enough food and there is a chance to take wing and fly away. Unless, of course, there are long frosts for several days. However, I agree that these are abnormally late clutches.
- What is the reason for such an anomaly?
The fact is that swallows have two nesting periods. They manage to hatch two broods. And if for some reason the brood dies, then they try to breed again, and this can continue up to four times if the broods fail. Another reason for late hatching is young birds. That is, if the parents are also from a late brood.
- Where do swallows spend the winter?
South Africa. Swallows are one of the most distant migrants of our fauna. Just like the white stork, which sometimes flies to Cape Town for the winter. This is how our barn swallow gets to the Republic of South Africa. 90% of our swallows migrate there.
- Has climate change affected the population of our birds?
Of course, for example, some birds stay with us for the winter, which has never happened before.
- For example, swans?
Well, swans are frost-resistant birds. They always wintered on the Black Sea. And now they also winter in the north of the country. However, only where there are open bodies of water. That is, where there are sources of hot water, for example, near a thermal power plant or hydroelectric power station, where the current washes away the ice. And there is nothing special here. But we have such a bird as the warbler, it is a rather small bird weighing only 10-11 grams. So the warbler has always wintered in Africa, but for several years now it has been wintering near Odessa. The birds have created a colony there and winter normally. True, this is the territory of a wastewater treatment plant and it is a little warmer there than in the surrounding areas.
- What other birds don’t fly away now?
Many, for example, starlings. 100 years ago it would have been impossible to think that they would spend the winter here. And now this is a common thing, especially in the southern and western regions of Ukraine. Also rooks, our rooks always flew to Europe for the winter. 50-70 years ago in Austria and France they spent the winter. And already 20 years ago they spent the winter in Hungary and the Czech Republic. And now that the winters have become warmer, they generally spend the winter in Ukraine. And rooks flew to us for the winter from the central regions of Russia. That is, people thought that rooks lived with us permanently, but in fact, ours flew to Europe, and birds from more severe regions flew to us. And now both those and ours remain on their territory. This is due to climate change.
And the number of birds is affected by climate change. Is there a statement that, in particular, there are fewer birds this year than in previous years?
This is an exaggeration. The fact is that each species has a long-term population dynamics. If you remember, in the post-Chernobyl years there were rumors that the number of sparrows had decreased. Indeed, there were not enough of them then, but this was in no way connected with the Chernobyl accident. There was just a natural change in numbers. For example, whether favorable conditions for reproduction exist annually or not. Have you heard about mouse years, when there are a lot of mice, and then there are few of them.
The same thing happens with birds. The last few years have been very dry: the reservoirs have dried up. Therefore, there were unfavorable conditions for nesting of waterfowl, their numbers were low. Even hunters complained that there were no ducks and nothing to hunt. This year the situation is similar, and if next year is rainy, their numbers will increase. Therefore, there is no point in complaining about climate change here. This year, let’s say, there were a lot of sickle wings, flocks of hundreds were rushing around Kyiv.
- Which birds have already flown away?
Our stork has already flown away; today he is already somewhere near the Bosphorus on his way to Israel. The sickle wings have already flown away. This bird is generally very strange. On July 30-31, flocks of sickle wings rushed around Kyiv, and the next day they disappeared - they fly away in one day. The same shore swallow is already flying away.
- Have some birds already flown to Ukraine for the winter?
Not yet. For example, bullfinches will arrive from Russia at the end of October. The waxwings will arrive sometime in November. Geese, swans, tits - in October. In fact, few birds come to us for the winter.
ANSWERS TO QUESTIONS IN THE KOSCHEY QUIZ from 12/10/2009.
1. Do swallows fly away from Russia for the winter? Not really
Yes
For the winter, swallows fly to hot countries. They fly away quite early and arrive relatively late - after all, they depend on flying insects, which appear in abundance only in the hot season.
All swallows are insectivores, catching flying insects, more precisely, those that are carried high up by the wind and currents of warm air rising from the ground. And swallows eat them in large quantities.
Swallows are “children of the air”; they land on the ground very rarely and reluctantly. In the air, they demonstrate the most complex aerobatics: dives, loops, glides and somersaults.
By the way, this dependence, or, more precisely, a direct connection, gave rise to a popular superstition: swallows fly high - the weather is good, if they fly low - it means rain. The sign is quite reliable, although the point here is not the swallows, but the insects. In stable, good weather, the air is dry, air currents lift insects high, and swallows fly (hunt) high. Before it rains, the air becomes humid. A person may not feel this, but the thin wings of insects get wet from this even insignificant humidity, and the insects drop. Swallows also descend after them. Insects are small, they are not visible, but birds are clearly visible - so a sign was born, associated not with insects, but with swallows.
2. Persimmon - VEGETABLE or FRUIT?
Fruit.
Persimmons are trees or shrubs with simple evergreen or deciduous leaves that grow in southwest Asia. The fruit is a bright orange fleshy berry with large brown seeds. Persimmon is very healthy and tasty. Sold in Russia in autumn and winter.
The Latin name for persimmon is “food of the gods.” The first gods to try this delicacy were Chinese, because persimmons come from China, where they have been grown for centuries. And today, in the vicinity of Beijing, you can find 500-year-old trees, and a bright orange ball symbolizes victory. Today there are more than two thousand cultivated varieties of this plant.
3. INDIA or CHINA is closer to Russia?
China.
China even has a common border with Russia!
4. Is a sweatshirt: PANTS, JOINT, HAT?
Sweater.
Sweatshirt is a very strange Russian word that denotes almost any sweaters, T-shirts, jackets, sweatshirts, warm vests and even vests!
According to the phenological calendar, after August 14, swallows and swifts are going to fly to warmer climes, to the very south of the African continent - to South Africa.
In the central regions of Russia, swifts usually leave for the winter around the twentieth of August. Swallows usually fly away later: shore swallows at the end of August, city swallows at the beginning of September. This year, these black hunters stopped being observed in Moscow after July 28th. There are two main reasons for the premature departure of birds to warmer climes - a sharp cold snap and a lack of food. .
Is it possible to judge the weather in the near future by the behavior of birds?
All swallows have amazingly developed sensory organs; they are able to navigate well in space and are sensitive to external factors. These long-tailed birds sense the approaching change in weather much earlier than humans; they are among the first to migrate to warm regions, but this does not mean that you should believe the sign and wait for the onset of the first frosts. Swallows tolerate cool climates well; in Russia they fly to the north much further than swifts, settling in populated areas even in the tundra zone. It happens that swallows and swifts fly south a few days before the cold weather, and one gets the feeling that they seemed to know about this in advance. It also happens differently: when swallows and swifts do not have time to migrate with the arrival of cold weather and die. Therefore, it is impossible to say for sure whether birds are flying away due to a sharp cold snap.
Hungry Runs
Another important reason for the early departure of birds is the disappearance of food in their habitats. Typically, swallows set off on their journey having accumulated large reserves of fat under the skin, in the muscles and liver, which they gain by feeding on mosquitoes, midges, flies and other arthropods picked up by rising air currents.
Swallows prefer to hunt not only at heights, but also on the ground, unlike swifts, which grab prey at heights and have no choice but to change their habitat before the onset of autumn. Weather changes affect the behavior of insects and their location in the air. In the event of severe bad weather and lack of food, swallows remain in the area where they are caught by bad weather, hide in shelters, and crowd together.
Every year it becomes more and more difficult for birds to find food in large cities. Thus, Moscow is completely covered with artificial lawns, which do not produce either flowers or seeds, which insects so need for housing and reproduction. In addition, insects are simply destroyed during lawn renovation work. As a result, in Moscow there are much fewer ants, butterflies, beetles, grasshoppers, locusts and caterpillars, which adults feed their chicks with. Frequent mowing of lawns also does not promote the reproduction of insects, since the plants die off before they have time to produce seeds. As a result, the soil, devoid of vegetation, dries out and burns out, depriving insects of the opportunity to feed on pollen and build their homes.
A decrease in the number of insects can lead to irreparable consequences not only for birds, but also for entire ecosystems, because they serve as a source of food for many reptiles, amphibians and other living organisms.
DID YOU KNOW?
In the 18th and 19th centuries, people were sure that swallows hibernate by climbing to the bottom of reservoirs and burying themselves in the silt. Fantastic, how could they then explain what the swallow was breathing? Even the great scientist of that time, an expert on many plants and animals, Karl Lineus, for some reason believed in this. Where did such a ridiculous legend come from? It turns out that swallows, before flying south, often gather in large flocks near the water, on the shores of reservoirs. Many people observed such a picture, but no one recorded the process of departure: they were there and suddenly disappeared - this led to the belief that the birds simply dive into the water until spring. In 1740, one German scientist, Johann Frisch, attempted to prove that swallows do not dive at all, but fly away. He was the first to think of tying red silk ribbons to the birds’ paws. And even after in the spring he managed to catch several swallows he had marked (and, of course, nothing was found on the strings) no one believed him. Another hundred years passed before another attempt was made in 1848 to prove that swallows hibernate. The Swedish Academy of Sciences has even awarded a prize to those who can find living swallows sleeping underwater. But, fortunately, no one got it. And only in 1899, when ornithologists began ringing all the birds, were they able to find out exactly where which pizzas spend the winter. Swallows were discovered on another continent - in Africa! It turns out that small birds fly thousands of kilometers from their native nests. Their route runs over the sea and even over the scorched Sahara Desert. Many of them climb to the very south of Africa. And in the spring they make the same journey again - they return to where they were born, to their nests from last year.
In this article you will learn about the name of the city swallow, get acquainted with its appearance, the life and nesting characteristics of this species. It can be seen on almost all inhabited continents, where it winters or nests. This is predominantly an urban bird, preferring to build nests on houses. The city swallow likes to circle in the upper layers of the air, rising to great heights before the onset of bad weather, and during and after rain it makes circles above the ground, catching the insects it flushes away. During such a hunt, it prefers a wide area for flight. She is rarely seen hunting in narrow alleys.
Although the funnel's voice sounds rather weak, it is heard quite often during flight. In most countries it is considered a sin to destroy the nests that this bird creates. The city swallow is slightly smaller in size than a sparrow. It is believed that if she settles under the roof of a house, this promises happiness to all its inhabitants.
City swallow: description
The upper part of the plumage is predominantly black, acquiring a blue tint in the light. The underparts from beak to tail are bright white, while the notch on the tail is quite shallow. The bird's feet are completely covered with feathers right down to the claws. Outwardly, it is impossible to distinguish a female from a male. In addition, there are no seasonal differences in plumage. Even in young chicks, the coloration is similar to that of adults, although the upper part of the body remains black and gray for some time.
The blue tint in young birds is rather weakly expressed, and there are brown stains on the sides and chest. Thanks to the bright white rump and the missing dark band, this bird is easy to distinguish among similar species even at a considerable distance. The average weight of a city swallow ranges from 18-20 g with a length of 15-17 cm. It is noteworthy that, despite the fact that the length of the wings does not exceed 12 cm, their span reaches 33 cm.
Lifestyle
Arrival in the spring is quite extended, most birds begin to arrive at the beginning of the greenery blooming, and the rest return only by the end of May. Previously, this species preferred to settle on rocks, but now their settlements can be found on stone buildings. In pursuit of prey, the funnel can reach speeds of up to 45 km/h, managing at this speed not only to feed, but also to quench its thirst. It flies over sources of water with its neck extended, thanks to which it manages to scoop it up with its beak.
In addition, during flight, they can take a complete swim several times, flying over the water. Swallows prefer not to descend directly to the ground, using mainly the tops of trees or wires to rest.
Habitat
They usually live quite peacefully among themselves, even preferring to create housing in groups. Unlike other birds, they do not have the need to protect the hunting territory, because in the summer there are enough midges for everyone. The city swallow is distributed throughout almost all of Eurasia, right up to the far north. At the same time, its distribution across cities is uneven; in different areas it can be either a common or an unusually rare bird. These migratory birds return to their native lands as soon as the first greenery appears on the trees, willingly settling into last year’s nests. In mountainous areas they nest in colonies, attaching the same nests on rocks as those they build in cities.
Nesting Features
With the onset of spring, swallows tend to return to the same area where they nested earlier. Usually the best-preserved nests are occupied by the birds that arrived first. Those who remain have to choose a place to build it soon after arrival, usually in the morning or evening. Most often, city swallows settle in colonies, in which there are from 10 to 100 nests. There may also be nests of individual pairs. The shape of their homes resembles 1/4 of a sphere. They build them under eaves, balconies, beams and other areas of the house protected from rain, creating nests from small lumps of damp dirt. The immediate timing of the start of egg laying directly depends on the conditions in which the funnel has to live, and the moment when the number of insects in the air increases to its maximum. For example, in the northern regions, the city swallow manages to hatch only one offspring, but closer to the central and southern regions there are usually two clutches.
Males are the first to appear in places suitable for living together, and they attract females, sometimes starting to build nests alone. However, most couples are formed during the flight, so often by the time the future home is arranged, the couple works together.
Protecting the nest from sparrows
The houses of city swallows can often be visited by sparrows. Most often, they occupy them at a time when the swallows have not yet completed construction, and the size of the hole in their home remains sufficient for the sparrow to fly in there without any problems. When the construction of the house is completely completed, the hole in it will be so small that a sparrow will no longer be able to penetrate. It is noteworthy that in the competition for housing, the struggle sometimes reaches a critical level.
In some cases, sparrows take over the nests of hoppers, often killing their immediate owners. At the same time, the swallows, seeing that they cannot drive away the invader, simply wall him up inside. Thanks to the universal construction technology, nests are kept in good condition for several years, so birds are provided with permanent nesting places.
Key points in arranging a nest
Funnel birds prefer to build nests close to each other. The main materials for construction are wet earth and small mud lumps. They find mud at the edges of puddles. In order to get the optimal lump of dirt, the bird vigorously pecks at the ground. In most cases, both birds build a swallow's nest. Depending on the weather conditions characteristic of the nesting period, the time required for construction rarely exceeds three weeks, taking for the most part from 3 to 10 days.
The nest is attached at the same time by both the side and the top. The entrance hole is located at the top of the nest, which allows optimal protection of the chicks from bad weather. The inside of a swallow's nest is lined with small feathers, down, soft fibers of plant origin, and pieces of dry moss. In the absence of these materials, birds willingly replace them with pieces of tow, thread and cotton wool. Its width on the outside rarely exceeds 30 cm, height 12 cm, and length 15 cm. On the inside, the height of the tray is rarely higher than 3 cm.
Masonry
The clutch contains about five white eggs with a very thin shell, which the parents incubate in turn for two weeks. The eggs have a sharply rounded blunt end and a gradually sharpening other pole. Newborn chicks have sparse light gray down. The chicks' oral cavity is yellow. A swallow chick is completely helpless in the first days of its life. That is why, for most of the day, the female warms the chicks, and the male provides them with a sufficient amount of food. In bad weather, the mother takes part in fishing, as a result of which she is forced to leave her offspring. City swallows prefer to hunt in clear weather.
When attacking insects, they fly up. At this time they can often be seen over open areas. In inclement weather, birds prefer to fly much closer to the ground and not as often. Unlike the village swallow, the city swallow feeds not only its chicks, but also the chicks in neighboring nests, without making significant differences between them and simply bringing the caught midge to the nearest nest.
Chick development
The duration of incubation depends on weather conditions and ranges from several weeks in good weather to a month in bad weather. Both parents are involved in incubation and further feeding of the young. The chicks stay in the nest for no more than three weeks. During this period, they manage to go through all stages of formation, become sighted and fledge, beginning to resemble adult birds as much as possible. At the end of the second week they already begin to fly out of the nest. At first, the swallow chick prefers to stay close to the nest, as the adults continue to feed it.
Only by autumn the young animals gather in flocks and begin, following the example of their parents, to lead a nomadic lifestyle, feeding independently until they fly away. In the fall, before flying to warmer climes, you can often see jackrabbits sitting on telegraph wires, wire fences, or flying high above fields and meadows. Since crowed birds are migratory birds, with the onset of the first cold weather you can see them flying to South Africa or southern Asia for the winter.
Feeding the chicks
During the period of feeding the chicks, funnels destroy a very impressive number of various insects. During the day, each parent flies up to the chicks with food about three hundred times. In addition, when feeding several broods over the summer, a pair of funnels catches about a million insects. The speed at which the chicks develop also depends largely on weather conditions. If there is not too much rainfall during the summer, it is not difficult for parents to provide them with the right amount of food, but if the weather is unfavorable, the chicks often have to starve. In the event of an early onset of cold weather, parents are forced to leave their chicks to die of hunger, going to warmer climes.
Caring for the chicks
The care of adults for the chicks comes down to heating them, constant feeding, cleaning the home from their feces, as well as repair and protection. Moreover, most often it has to be protected from swallows that have not yet managed to build their nests. In the first days of life, the chicks receive minimal portions of food, consisting exclusively of small insects.
During the first week after the chicks hatch, there are breaks in heating on the part of the parents, and later they completely stop warming the chicks during the day, concentrating exclusively on getting food. At the age of one week, the chicks sit during the day mostly with their heads raised, due to which the feeding procedure is significantly simplified. Chicks aged two weeks and older are characterized by pecking movements.
What do barn swallows eat?
Funnelfish eat mainly flying insects: from small beetles to midges. It is much less common to see catching butterflies, grasshoppers and spiders. Birds prefer to hunt for insects by flying in open areas. In inclement weather, they try not to hunt, waiting out this time in the nests, or fly indoors to warm up and dry out, huddling in heaps in attics. During prolonged bad weather, an extremely large number of swallows die, which cannot tolerate a prolonged period of torpor.
Flights
City birds, including hornbills, prefer to fly south in small groups or in a continuous sparse and amorphous stream, flying exclusively during the day. The period of departure from large cities begins mainly in August; in the steppe zone it can last until the beginning of October. They winter mainly in southern Africa and Asia.
Attracting swallows to cities
Crows can be attracted to nesting artificially. The only thing you need to do for this is to equip artificial nests, constructing them in the likeness of real ones. As the main material, gypsum, cement mixed with sawdust are perfect. In the absence of these materials, you can even use papier-mâché, which is hung under the roofs.
It must be taken into account that all city birds, including swallows, will be much more willing to settle in your city if they find a sufficient number of suitable nesting places. It is for this purpose that special shelves should be nailed under the eaves or containers with wet clay should be placed outside the windows. If there are also places nearby where swallows can catch insects, then they can easily be attracted to your area.
Despite its miniature size, the funnel swallow is a tireless worker. Seeing their appearance in the spring, we joyfully and impatiently await the warmth and understand that spring has come. This is probably why all people love these first messengers of warmth and deeply believe that birds settling under the roof of a house will bring happiness to its inhabitants.
Just some 200 years ago, people could not even imagine that birds would travel thousands of kilometers to spend the winter in warmth and comfort. What kind of inventions did ornithology (the science of birds) know?
Aristotle himself believed that many birds, including swallows and kites, hibernate during the winter, and some even transform into another species. According to the philosopher, the redstart, which he observed only in the summer, in the fall turns into a robin, which the scientist had to see only in the winter.
Many scientists listened to the fantastic versions of Aristotle, who lived before our era. Even a couple of centuries ago, they were sure that swallows and swifts hibernate at the bottom of lakes, immersed in silt. There were also those who considered the birds too fragile to cross seas and oceans, so they “sent” them to the moon to spend the winter! Europeans and North Americans believed that small birds traveled on the backs of large ones.
Sensational discovery!
However, on May 21, 1822, a sensation spread around the world! Nearby German Mecklenburg An 80-centimeter arrow was found in the body of a dead stork, piercing the bird’s neck. The arrow was not from here and belonged to one of African tribes. A desperate brave man with an arrow in his throat managed to overcome the entire migration route, returning home from the equatorial wintering grounds.
This story shed light on the mysterious disappearance of birds in winter. A stuffed specimen of the famous arrow stork can still be seen in the zoological collection of the University of Rostock.
Repeated reports of African arrows in their bodies helped make the discovery that European birds winter in equatorial Africa. However, ringing, which naturalists began to carry out since the 90s of the 19th century, made it possible to accurately determine the places where birds fly to for the winter.
Where do birds fly for the winter?
It is believed that the founder of ringing was a Danish science teacher. Hans Mortensen. The man hung light aluminum rings on the swallows that were hanging around the school. A year has passed - and the birds are back! This was the first attempt to mark birds.
By studying the migration of swallows using banding, scientists have determined that these little daredevils reach South Africa. Transcarpathian swallows, for example, cross the Sahara and spend the winter in Central Africa. She was chosen and Ukrainian nightingales. These are complete migrants.
However, there are also partial ones that migrate nearby. Starlings, living in the UK, remain in the country throughout the winter. Scandinavian starlings also fly here for the winter, sharing the territory with resident birds.
Cranes winter in Iran, India, Iraq or Africa. Larks fly to India or north Africa. Cuckoos spend the winter months in southern Asia or Africa.
The champion of long-distance flights is Arctic tern, inhabitant of the Arctic. Every year a bird flies to the other end of the Earth, migrating from the North Pole to the South Pole. Spends the winter in Australia and Antarctica. Interestingly, the tern does not fly in a straight line, covering 30–40 thousand kilometers per year.
At what altitude do birds migrate?
Most songbirds migrate at altitudes of 500–2000 meters. And this is the height of 2-4 Eiffel Towers. Some winged birds rise almost 7 kilometers above the ground. Swans were observed at an 8-kilometer distance from the ground, and bar-headed geese were observed at 9 kilometers above the ground.
Small birds can fly continuously for 70–90 hours, flying four thousand kilometers. Their flight speed is 30 km/h. Large birds migrate at a speed of 80 km/h.
How do birds find their way when migrating?
There is still no clear answer to this. Scientists believe that the behavior of birds is governed primarily by instinct. To test this hypothesis, the Dutch scientist A. Perdek conducted an experiment with starlings.
Having ringed several thousand birds, he transported them from the Netherlands to Switzerland and released them into the wild. Young birds, migrating for the first time in their lives, went to the southwest. Thanks to instinct, the starlings managed to choose the right direction. But in the end they deviated from the course and ended up significantly south of the wintering place. The young birds had no choice but to spend the winter in Spain and the south of France. And adult starlings, who had experience of seasonal flights, showed that they have sniper navigation and are perfectly oriented in space. The birds immediately laid out a new route to the west and northwest, easily reaching their usual wintering place - Great Britain.
During the day, the key landmark for birds is Sun. Birds are able to see polarized light, so they can easily find their way even during bad weather.
Gustav Kramer, who observed starlings in captivity in the 1950s, decided to test the orientation of birds by the Sun. With the onset of spring, the birds flocked to the northeast. Even when their cells were rotated in different directions, the direction did not change. Then the scientist changed the location of the mirror system so that the sun's rays fell from the opposite side. And - a miracle! - the starlings changed direction to the opposite.
However, Kramer's new experiments, when the artificial star did not move, showed that in the fall the birds are still restless and tend towards their usual wintering places. This proved the presence of birds internal clock, by which they determine the time of day and year.
Of course, when migrating, birds are guided by landmarks- location of mountains, valleys, river beds. This is how they find familiar places for food and rest.
Birds look for a way at night by the stars. This hypothesis was first tested by Franz and Eleanor Sauer. When scientists brought the birds to the planetarium and turned on a star map of the autumn sky, the birds flew to the southwest. And when the star map was changed to spring, the birds quickly turned to the northeast. While you are surfing the Internet at home, the birds, while still in the nest, are studying a map of the starry sky!
What if the sky is covered with clouds at night? Another landmark for winged travelers - magnetic fields. The Earth is a giant magnet, with magnetic field lines stretching between the South and North Poles. The bird's brain contains a special organ that is capable of recording these fields. Iron particles in the beak also help the bird determine its location relative to the Earth's magnetic field.
A large number of birds (geese, swans) learn the route of seasonal flights, migrating with experienced relatives. But the cuckoo has to find its way on its own, thanks to its innate instincts.
Why do birds migrate?
The reason is not only frost and lack of food. With the onset of cold weather, many birds unjustifiably fly further south than necessary for a comfortable wintering. But why? Scientists are inclined to believe that this is a relic of the past, a genetic memory that pushes birds south, as in the distant times of the Ice Age.
Why don't birds stay in warm regions forever? In a foreign land, many dangers await them: predators, rainy seasons, droughts and poachers. If European birds had remained in Africa, a fierce struggle for water, food, and living areas would have begun. It would be difficult for migratory birds to compete with resident birds. In the north, there is a favorable climate for nesting, more food and fewer dangerous predators.
Every year brings new discoveries that explain many of the mysteries of bird migrations. Often, research results completely reject previous theories. Solving old riddles leads to the emergence of new ones, and it seems that their number will not decrease while noisy bird caravans fly up into the air...