Secondly, swallows actually spend a lot of time catching bugs in the sky, on the one hand to feed themselves and on the other hand to feed their offspring. But as long as winter comes, even if the swallows are not afraid of the cold, the insects who are afraid of the cold will choose to hibernate. At this time, swallows will have no food to eat, so they will fly to a warm place to ensure food. Moreover, the place where swallows fly is summer, with long days and short nights, so they can feed.
Since swallows fly to a warm place every year, why not choose a place where there is plenty of food in long summer and no winter, so that you don't have to spend so much energy and physical strength to fly to the right place every year. For example, the tropical rain forest area near the equator can receive direct sunlight twice a year, which is hot all year round, with abundant rainfall and extremely high temperature. This perfect combination of water and heat makes it diverse in species and rich in biological resources.
Everything sounds particularly suitable, but it is still analyzed from the climate in the equatorial region. It is precisely because of good hydrothermal conditions and abundant species resources that the equatorial region basically has it? Overcrowded? Now, there is no room for swallows to come. Even if the swallow really chooses to fly, even if it is so petite, it can't grab food from other species and will only starve to death in the end.
In addition, swallows will lay eggs and breed soon after arriving at their destination. How can swallows breed without habitat? On the contrary, spring and summer in some temperate regions are the seasons when everything grows. It's a vast territory, and swallows fly around here without worrying about habitat and food. Why not?
Of course, what if swallows can choose? Settle down? They don't want to run around. Because their migration generally spans the northern and southern hemispheres, chasing warmth. Along the way, they need to climb mountains and cross the arid desert. During the annual migration, many swallows always die.
Moreover, in recent years, some unreasonable human activities have caused adverse effects on the ecological environment, and also affected the migration of swallows. Swallows are good birds for human beings. In order to make the song "Little Swallow" continue to be a household name among our younger generation, perhaps human beings should really live in harmony with nature.