Why do swallows fly around instead of staying in the warm south all the time?

<> some people will say that it is because swallows are afraid of the cold, so they need to fly to warm places. Actually, this idea is very correct, but it is not comprehensive. First of all, swallows are so common that there is no shortage of opportunities to observe them, and we have the impression that swallows have not many feathers, but they are also thick, so they are not so afraid of the cold.

Secondly, swallows actually spend a lot of time catching insects in the sky, on the one hand, to feed themselves, on the other hand, to feed their offspring, but as long as winter comes, even if the swallows are not afraid of cold, insects that are afraid of cold will choose to hibernate, at this time the swallows have no food to eat, so the swallows will fly to a warm place to ensure that there is food to eat, and the place where the swallows fly is in summer, the days are long and the nights are short, and the time to forage for food is even longer. ensured the needs of their lives.

Since swallows fly to warm places every year, why don't they choose a place where there is no winter and plenty of food to live in, so that they don't have to spend so much energy and physical energy to fly to the right place every year? For example, tropical rainforests near the equator.

The region, which receives direct sunlight twice a year, is hot all year round, has abundant rainfall and extremely high temperatures, and this excellent combination of water and heat makes it a diversity of species and a very rich biological resource.

It sounds like everything is particularly suitable, but still from the equatorial region.

It is precisely because of the good water and heat conditions and rich species resources that the equatorial region is basically "overcrowded", and it is impossible to tolerate the arrival of swallows, even if swallows really choose to fly, they are so petite that they are afraid that they will not be able to snatch food from other species, and they will only starve to death in the end.

Moreover, swallows lay eggs and breed soon after they arrive at their destination, so how can swallows reproduce without a habitat? On the contrary, in some temperate regions, spring and summer are the time when everything grows.

During the season, the territory here is vast, and the swallows fly here, so why not worry about the habitat or food?

Of course, swallows don't want to run around if they can choose to "settle". Because they generally have to migrate across the northern and southern hemispheres, chasing warmth. All the way, they need to cross mountains, rivers and seas, pass through arid deserts, and many swallows always die during their annual migration.

Moreover, in recent years, some unreasonable human activities have caused adverse effects on the ecological environment, which has also affected the migration of swallows. Swallows are beneficial birds for human beings, in order to be able to make the song "Little Swallow".

Continuing to become a household name among our descendants, human beings, perhaps, really deserve to live in more harmony with nature.

In order to reproduce offspring. In order to reproduce, swallows need to fly around and cannot stay in the warm south forever.

Although the swallow itself is not afraid of the cold, in winter the swallow flies to a place of temperature for the winter, the main purpose is to feed and breed their offspring, in the cold place in winter, the insects all hibernate, and the swallow cannot feed its own children.

Because the south is not always warm, only the summer is warmer in the south, and the winter is very cold, so the swallows have to fly to another place to spend the winter.

Swallows fly south in winter, to South Asia or Southeast Asia.

In fact, the south of the swallow is not what we often say about the north and south of the Qinling Mountains and the Huai River, the south is just a relative statement, generally China's swallows have to fly to South Asia or Southeast Asia, like China's Hainan area, and some can even fly through the equator to the southern hemisphere.

In the autumn before winter comes, swallows make their annual long journey, flying in flocks from the north to the far south. The time for swallows to fly south varies according to different regions, for example, in the northeast region, it starts in mid-August, and when it arrives in Shandong, it is after September.

On the surface, the winter in the south is warmer, while the winter in the north is colder, and the swallows have to fly to the south to escape the winter, and then return from the south to the north when the spring flowers bloom. In fact, this is only one reason, the root cause is the reason for food, swallows feed on insects, and there are no flying insects for swallows to hunt in the northern winter.

The habits of the swallow

Swallows are very flexible and spend a lot of time in the air every day to hunt, they mainly live in tree cavities, sandy banks to nest, and will stick mud to the walls of urban and rural corridors, roofs, eaves, or protruding from the wall for nesting; They feed on mosquitoes, flies, and will take the initiative to hunt specific prey; They generally breed in April and July, and the parent birds are fed together with their young, laying 3 7 eggs each; In winter, they move to warmer areas for the winter.

House swiftlets nest under the eaves of farmhouses, where they bind mud and grass stalks with saliva and cover them with soft weeds, feathers, rags, and some Artemisia annua leaves. 14 At 15 days, the young birds emerge from the shell and are co-fed by the parent birds. The chicks fly out for about 20 days, and can feed themselves for another 5 to 6 days.

In the south, there will be a rainy season in summer, which is more humid, but in the north the temperature is moderate in spring and summer, the climate is dry, and the living environment is more suitable for swallows, so they only go to the south in autumn and winter to spend the winter, and return to the north in spring and summer.

Because survival needs; Swallows fly back and forth every year to come to the south in the spring to breed their offspring, and then fly back to the north to live.

Because the winter in the north is very cold, if the swallows come to the south, it is also to escape the cold of the winter, plus there is no food in the winter in the north, so it is a good choice for the swallows to spend the winter in the south.

Because swallows are migratory birds, they choose their habitat according to changes in climate, so they do not stay in the south all the time, and they fly back and forth every year according to changes in temperature.

Summary. This has to do with the Earth's axis of rotation. The axis of rotation has a certain inclination, and it is precisely because of this inclination that the earth produces the phenomenon of "four seasons all year round". Therefore, the axis of rotation may also affect the judgment of the swallow's flight distance.

Why didn't the swallows stay in the south all the time? Why fly back and forth every year?

This has to do with the Earth's axis of rotation. The axis of rotation has a certain inclination, and it is precisely because of this inclination that the earth produces the phenomenon of "four seasons all year round". Therefore, the axis of rotation may also affect the judgment of the swallow's flight distance.

This can explain clearly, if the swallow stays in the south all the time, it is not good, because the south also has a cool moment, and after the cool, the swallow will leave to fly in the north direction.

Swallows in China migrate south and north in a regional gradient. Most of the common swallow wintering grounds in China are Southeast Asia and South Asia, and some swallows also wintering there on the border of Yunnan. Beijing Louyan moved to South Africa.

The distance traveled by different species of swallows also varies. Every spring and autumn, swallows migrate in flocks along a relatively stable route. The "southern" destination of swallow migration distributed in China is not the southern region south of the dividing line of the Qinling Mountains and the Huaihe River, but generally selected in Hainan, Yunnan and other tropical regions, and some species of swallows fly south out of the country to Southeast Asia, South Asia and other more southerly regions, and travel tens of thousands of kilometers.

Some swallows can fly over the mountains to India, while others can cross the equator and fly to Australia and other places for the winter. European swallows are more persevering, and they also fight hard to survive the winter, crossing the Mediterranean Sea and then crossing the Sahara Desert to southern Africa.

Extended Materials. Why do swallows fly south?

The winter in the north is not conducive to insect reproduction, some insects are frozen to death, some enter a dormant state to hide, due to the lack of food, swallows themselves do not have the habit of hibernation, in order to make a living, forcing them to fly to the southern tropical areas where there are insects to eat before winter comes.

Winters in the tropics tend to have plenty of food**. On the way south, swallows also fly and hunt at the same time. In the south, they only need to do one thing, which is to eat and drink enough, and the time there is still relatively leisurely.

Why do swallows fly back north in the spring?

Since the climate in the south is like spring all year round, and there are always enough insects to eat, the swallows have crossed thousands of mountains and rivers before migrating to the south, why not stay all year round? And what about returning to the temperate northern region in April next year?

In the southern tropics, the vegetation is abundant and the biological diversity is diverse. The tropics are much more diverse and abundant than in the north, and competition for food and habitat is intense. Whereas, swallows are petite in size and gentle in nature, so they do not have a competitive advantage.

Moreover, the south is rich in species, and there are many natural enemies of birds, such as birds of prey, snakes, and birds under the eagle family, which are obviously not conducive to reproduction and raising the next generation.

1. In the past 40 years, reform and opening up, capital investment, demographic dividend, etc. have promoted rapid economic growth, as global economic activities are moving to the most populous regions, aspiring and talented people prefer to live in a few cities and regions, and cities across the country have also started a "war for talents", which has evolved into a "war for talents", 2. Promoting the development of preschool education is the support of human capital, and increasing high-quality public and GSP preschool education can promote the upgrading of human capital from the source, and contribute to balancing income inequality and economic growth and social justice; The supply of high-quality and sufficient pre-school education can reduce the cost of childbirth and promote population growth. Attaching importance to the development of preschool education in developed cities will help build a growth pole for regional economic development and lead the "high-quality" growth of China's economy.

Among the birds, there are many migratory birds, and they all have migratory habits, such as what we often call "wild geese flying south", which is the beginning of the migration of wild geese from the north to the south. Most migratory birds migrate from north to south, which is directly related to topography, vegetation and weather. Among all the birds, the closest bird to people is the swallow, which likes to settle in human settlements and live next to people, and it is also a typical migratory bird.

So, why do swallows fly thousands of miles from the north to the south? And why don't swallows stay in the south where the seasons are like spring? Let's look at these two questions from a scientific point of view.

Why do swallows "fly south"? Hungry hands.

The swallow is a worldwide bird, among which our common house swallow is the national bird of Austria, and the swallow is also a more popular bird in our country, which shows that the swallow is very popular everywhere. The reason why swallows are popular is that in addition to the fact that they like to be neighbors with humans, it is also very important that the main food of swallows is insects, and most insects are pests for us humans.

However, swallows in any country or region have migratory habits. Take the swallows of our country as an example, in October every year, the swallows living in the north will gather together, and then head to the south of our country. Its journey is more than thousands of miles, so regret Jane, why did the swallow fly south?

There are two reasons for this: blue-limbed pants.

01 Cold.

In the north of our country, the weather gradually cools down from mid-October every year, and then it will enter the cold winter, and although swallows have feathers on their bodies, they have the ability to keep out the cold.