Winter of Lagerstroemia indica in North China

"The swallow wears colorful clothes and comes here every spring ..." This is a classic nursery rhyme known to all ages, and many children can sing it. Every winter, swallows return to the south for the winter. And when the next spring, the swallows will fly back from the "South". However, many people are curious. Why don't they see the swallows in winter when they are obviously from the south? Where is the "South" in the saying "Swallows fly to the South for the winter"? In fact, many people have misunderstood that the "south" of swallows is far farther than we thought! Swallows are beneficial birds that mainly feed on mosquitoes and are friends of people. They spend a lot of time catching pests in the air. But when the weather is cold, swallows will migrate from the north to the south for the winter. The weather in the south is warmer. Why do swallows fly back from the south to the north in spring? Why don't they stay in the south?

Swallows are beneficial birds that mainly feed on mosquitoes and are friends of people. They spend a lot of time catching pests in the air. But when the weather is cold, swallows will migrate from the north to the south for the winter. The weather in the south is warmer. Why do swallows fly back from the south to the north in spring? Why don't they stay in the south?

It's cold in winter in the north, and it's a few degrees below zero in many places. It will not only snow, but also freeze. Many people think that swallows fly to the south because of the cold, and they mainly go to the south to avoid the cold weather. Actually, it's more than that. Swallows have thick feathers, so it is absolutely no problem to resist the general cold. An important reason for flying to the south is that many insects hibernate or freeze to death in winter in the north, and food is very scarce, so they have to fly to the south to find food.

Swallows' flying ability is still very strong, and they usually migrate in groups, but many of them always fall behind and die on the road in the process of flying to the south. Although the weather in the south is relatively more comfortable than that in the north, why do swallows fly back from the south to the north in spring after flying to the south and crossing Qian Shan?

This way looks silly, because the weather in the south looks more suitable for their survival, so why fly back? In fact, it is mainly because swallows are migratory birds, and their migration is mainly an adaptive behavior to changes in the surrounding environment. Climate change is the most important reason for migratory birds to migrate. When they return to the north in spring, they will breed and nest under the eaves.