China has a vast territory and rich products, which are greatly exaggerated in the east, west, north and south, but one custom is the same, and that is to take care of swallows. Swallows never bring trouble to people. They always eat all kinds of bugs, which are good for people and crops. Therefore, people everywhere regard swallows as a symbol of auspiciousness and harmony. There is a saying: Swallows only fall in good families. It shows that the place where the swallow is willing to come is auspicious.