"Little swallows wear floral clothes and come here every spring. ”
We all know that every year it's almost winter, the swallows will fly to the warm places in the south and come back next spring.
It can keep you warmWhy should the swallows fly south, then this"South" is **？Since the journey of the flight is so far away, theyAnd why did it fly back again in the spring?？Why not continue to breed in the south?
——The congenital conditions of flying south·]—
First of all, we need to first understand the creature swallow, mentioning swallowsWe all think of their scissor-like tails, wearing a black tuxedo-like smooth body, is a common type of creature in children's writings.
Then from a biological point of view, swallows are a group of migratory birds, they are generally small, very flexible in body, and extremely fast in flightTheir tails are not meant to be decorated for beauty, but to allow them to steer themselves at high speeds.
Swallows are very intelligent creatures, they also have their own knack for flying so fast, they are born to use the principle of airLet yourself float on a flat surface, thus reducing drag during flight.
Swallows basically have to cross many places every year when they fly south, and the flight journey is frighteningly long, which is also a small meaning for them to startBecause they never starve themselves on their journey.
It is due to the very high sharpness of the swallow's eyesightTherefore, whenever the swallow sees a prey in the air, it will immediately swoop down and pick up the worm at a very fast speed to leave, without dragging mud and water at all.
And we also know that swallows are very fond of building their nests under the eaves of human houses, and swallows are also first-class architectural geniusesYou can build your own house with your own salivaAnd it's so strong that it doesn't stand in the wind or rain.
So whenever the swallow flies tired,It may go to a random house to build a nestWait until you have rested in the past few days, adjusted your physical strength, and then continue your journey.
Therefore, whether it is from the swallow's own physical condition, or its ability to fly, or their hunting skills and nesting skillsAll so that they do not have much burden during the flight.
——Why fly south·]—
So why did the swallow have to fly south?, what is there in the south that attracts swallows and must go, so that swallows are thousands of miles away, and they still struggle to reach despite setbacks?
In fact, we also know that the general breeding season for swallows is in springAnd if they choose to go south in winter, they will have to drag their families with themIn fact, this is also a big challenge for the swallow.
Many people think that the swallows flying to the south must be because winter is coming, the weather is getting colder, and it is no longer suitable for lifeAnd the south is warm and the temperature is suitable, which is a good place.
In fact, this statement is completely wrongBecause the swallows' feathers are very warm, enough for them to resist the winter cold, and besides, their subcutaneous fat is also very thick, so the swallows do not feel cold in snowy weather.
What prompted the swallows to fly south was the food thereBecause when winter arrives in the north, almost all the flowers and trees are withered, and the swallows have no habitat to fly freely.
Otherwise, when winter comes, all insects, including swallows, will be foodBasically, it's all dead dead, wounded woundedMany of them hibernate directly into the ground, so the swallows have no winter rations.
So if the swallow doesn't want to fly south, stay in the northThey just have to go hungryYou know, the winters in the north are dry and long, and the swallows will starve to death sooner or later, so they have no choice but to fly south.
"South" is **
It is said that swallows fly south, so did all the swallows really fly to the south? Is the so-called south the south of the Huai River area of the Qinling Mountains in the traditional geographical sense?？So how far will they have to fly to get to their "south"?
According to a study, where swallows are going to fly,They are at least tens of thousands of kilometers away from where they begin to fly, which means that their flight will take at least one to two months.
In fact, the place where the swallow flies is not necessarily the south in our mouthThey had to cross the continents of Asia and Africa and finally reach South AfricaThat's where they end up in winter.
Because it's winter in the north,On the contrary, the season in South Africa is springIt was the best season on that continent, warm and comfortable, a paradise of their dreams.
The warm spring of the South African continent is full of revivalMany insects also crawl up from the groundAnd after a winter hibernation, they are also very delicious, just like the meal on the plate of the swallows who are tired from the journey.
So,The south where the swallow flies should not logically be the south of China, but the south of the earth, and they span not China, but half the world.
However, due to various differences in the size and age of the swallows and their food storageSo not all swallows will fly south,Some may not be able to fly halfway, so they find the eaves of a family to settle down, and some swallows may find a warm area that is more suitable for their own living, so they choose to live temporarily.
It is worth affirming that the swallow in order to reach the destination of the flight,Most of them travel in groups, ranging from a single family member to dozens or hundreds of swallows flying together, just to not fall behind halfway, to ensure that everyone can fly to the south together for the winter.
- Why do you want to come back?
Since it stands to reason that the swallow finally flew to the warm south in winter, it can be said that it took a lot of effortThen why do you have to fly back to the north en masse next spring?？If you calculate the time, the south was not as cold as winter at that time, and there was still food.
In fact, the swallow chose to continue to fly back to the north in the spring of the following yearBecause spring in the north is the best time for them to reproduce, both the temperature and the food are very conducive to their reproduction.
First and foremost, the most important reason is foodIt is said that people die for money, and birds die for food, and this sentence is not false at all on swallowsAccording to incomplete statistics, an adult swallow eats about a few hundred bugs a day, which is an astonishing amount.
Therefore, even if it is not yet winter in the south, and the food is still available, the swallows do not dare to joke about thisAfter all, it's almost the season of reproductionIf you don't eat enough, it will directly affect the development of the baby swallow.
What's more, the south has always had a humid climate, and once spring passes in the south, it is time for rain in summerIt was rainy all day, and it was a very vivid trip for swallows to go out hunting.
So the swallow can only accelerate back to the north,And it just so happens that the north has ushered in its spring, the season of recovery, which is the most suitable for swallows to hunt, and their food will not have to worry.
Then there is the fact that the diversity of life in the north is not as rich as in the south, so the swallows fly to the south, and their natural enemies increaseWhen hunting, you must always pay attention to whether there are ** hunters staring at you, so to speak, is apprehensive.
This is not the case in the North, where there is not as much biodiversity as in the SouthTherefore, in the north, swallows also have fewer natural predators, so if the swallow is going out hunting, it doesn't have to worry too much about its children being alone in the nest.
Finally,Another very important reason is the dry climate in the north, so the roof is relatively flat, which gives the swallows a lot of convenience to build their own nests.
And the flat roof can shelter the swallows from the wind and rain, so whether it is windy or rainy, once the swallow's nest is successfully builtThe wind and rain didn't get it at all, so it was a great place to stay.
To sum up, all the conditions in the north are very favorable for swallows to reproduceWhether it is from the food**, weather factors, nesting convenience and the invasion of natural predators, the north really gives the swallows a very great guarantee.
——Conclusion·]—
Flying south every winter and back the following spring is not a simple migration.
From the flight of the swallowWe can also see their indomitable will and tenacious struggleThey fly all the time on the road and complete this great trip on time every year.