The statements in this article are based on reliable sources and are repeated at the end of this article
"Little swallows wear floral clothes and come here every spring", this nursery rhyme should be sung by every child, and it has been a classic for so many years.
But everyone knows that swallows fly south, but do you know where the "south" here refers to? Is it what you think is southern China?
In fact, there are only 4 species of swallows living in the mainland, and the more common ones are golden-rumped swallows and house swallows.
House swallows are commonly known as swallows, they mainly feed on insects and hunt in flight.
But we know that many insects freeze to death when the temperature is cold, so they will have eggs or pupae as self-protective forms to facilitate their wintering.
This leads to a decrease in food for swallows in the fall and winter because they do not have the means to open the soil on the ground like chickens do, because the beaks are short and not sharp enough.
In winter, if they want to overwinter in the northern hemisphere, their feathers also need to become very heavy, which will bring a lot of pressure to fly and consume a lot of physical energy, so there are swallows flying south.
Unlike the south south of the Qinling Mountains and the Huai River line, most of the places where the swallows fly south will be beyond the country to Southeast Asia or across the ocean to Australia and other places, and only a few will be in warm areas such as Yunnan and Guangdong.
Because the weather and environment in the south do not have much impact on the life of insects, they do not need to worry about food if they fly there.
In this way, the swallows migrate very long distances, and during this time, they need to prepare for the accumulation of a large amount of fat.
However, too much fat will affect their flight, so the amount of food they eat also needs to be accurately calculated.
Swallows are relatively small in size and have many predators in the air and in the wild, or animals that can easily insert them into their bellies.
Therefore, for the safety of their lives, they will gather together before migrating, and their large numbers and some formations can help them disperse predators.
During their migration, there are many environments such as grasslands, forests, and mountains, and the route is a great test for them.
Swallows have thinner legs because most of their muscles are on their wings, so some swallows can sleep or hunt during flight, and do not need to be on land.
They are natural meteorologists who can accurately perceive changes in air pressure, wind direction, etc., and adjust their flight attitude.
In order to study the migration pathways of swallows, a scientific research institute installed a satellite positioning system on the swallows, which showed that they flew all the way west from Beijing and finally south.
That is, after passing through most of Africa from the mainland, it reached South Africa, which is a journey of tens of thousands of kilometers.
However, different house swallows have different migration paths, some will choose to go to South Africa for the winter, and some will go to Southeast Asia or the southern provinces of the mainland mentioned above.
If you see a swallow in winter, it's a swift, and its magnetic ability allows it not to get lost and return accurately.
So if the conditions in the south are more suitable for them to live, why not breed in the south, but fly back from the south every year?
Generally speaking, the north in spring and summer is the golden period for swallow brooding, because when spring comes, some insects will crawl out of the silkworms or eggs, and the life of swallows will become relatively easy after more food.
And because of the weather environment in the north, there are not so many species compared to the south, and the competition between food chains is not too fierce.
For swallows, there is no need to compete with other species, and the south cannot satisfy their need for large quantities of food.
There is a data that proves that in the north, each nest of swallows can hatch 4~6, while in the south can only hatch 2~3, which is influenced by sufficient food and a small number of competitors.
A very important human influence is that most of the houses in the north are bungalows or villages, which are a natural brooding ground for swallows.
Generally speaking, swallows returning from the south are ready to build their nests after a simple trimming, and if they have their own nest before, they will pick up some new mud to trim it.
But if there is no old nest, a new habitable location will be found.
Swallows, like us humans, are monogamous, so they built this home together, and once the location is determined, it is likely to live for several years.
This requires a lot of consideration when choosing a location, as most swallow nests are grass roots and dirt, and it takes more than 10 days to build even two swallows together.
In addition, in order to make it easier to live, they will also spread some fine grass and feathers to form a warm and comfortable environment.
Therefore, such conditions require them to be built indoors or under eaves, rather than on tree branches, because then they will not shelter themselves from the wind and rain, and even expose themselves to predators.
Therefore, the eaves of human beings have become their first choice, which can avoid both violent storms and predators.
It is often said that the swallow is a good bird, and the good here is a manifestation of everyone's love for it.
Because they mainly eat some pests, which is very helpful to crops, people naturally like them, and most of the time they do not poke the nest at home and drive them away.
So what does the swallow's big self symbolize under the eaves of humans? Is it good or bad?
The verse "On the eve of Wang Xie Tang, he flew into the homes of ordinary people" generally refers to the rich and noble families in ancient times, because at that time, swallows could only be found nesting in the homes of rich people.
After all, the location of the rich family is definitely better than that of the poor family, and the quality is more secure and stable.
They don't like dirty and noisy environments, so at that time, they thought that if the swallows nested in their homes, it meant that their family's living standards were high and their sanitation was guaranteed.
In modern times, most people think that if they have swallows nesting in their home, it is a symbol of good fortune and luck.
But not all birds nest under our human roofs, and some also build in the wild.
Now you know where the swallow flies to the south, right? The next time someone asks, you'll have to explain it to them.
Reference Sources:
Popular Science Times - May 14, 2024 Where exactly is the "south" to which migratory birds fly?