First, swallows usually build their nests with mud and hay. If they nest outside, they will collapse when it rains.
Bird's nest is very warm, but it has a fatal disadvantage that it is not waterproof. Swallows usually hatch eggs in summer, and this season is characterized by rain. Therefore, for the safety and health of future generations, swallows choose to nest under the eaves of human beings, which can resist the troubles caused by bad weather.
Second, although swallows don't like humans, there are almost no natural enemies of swallows where there are humans, so swallows can safely hatch eggs and feed them to birds.
Swallows, as animals that wear tuxedos all the year round, are not docile, but they have no actual attack ability. If they encounter natural enemies, they can only fly high, so the choice of nesting location is very important. After all, eggs and young birds can't fly and can only be eaten by natural enemies when they are in danger. So after selection, they think that human beings are the most suitable under the eaves. After all, where there are human beings, there are no snakes, wolves, tigers and leopards. Such an environment is a good place for them to reproduce.
3. Swallows' rations are mainly flies and mosquitoes. If people nest under the eaves, they can avoid mosquito bites.
Swallows living under their own eaves will pollute the courtyard environment, but it is not without benefits. Because swallows mainly feed on mosquitoes and flies, these two creatures rarely exist around their chosen place of residence. Because they ate them up, as long as the swallows are in your house, you can spend the summer with the insects flying all over the place.
Yan Zichao