First, the only swallows nesting in our house are domestic swallows and golden-waisted swallows. The reason why people choose to nest on the eaves or roof beams of human beings is mainly determined by the structure of bird's nest. Swallow's nest is mainly made of soil, and then mixed with grass stems, feathers and other materials. It is often two couples who cooperate to destroy their hearts bit by bit. After fully mixing with their saliva, stick the soft soil on the wall bit by bit, add some branches and grass stalks to strengthen the nest when eating, and finally gradually form a bowl-shaped nest. It seems like a simple step, but it takes more than half a month. Finally, it will be carefully covered with a layer of soft feathers or fine grass, thus building a comfortable nest. But there is no water in this nest. If this kind of house made of mud lives in the wild, it basically collapses when it rains, so it can only be built in a place where it can shelter from the rain.
Second, in the wild, the only place that can completely shelter from the rain is usually a cave, but caves are also places where natural enemies such as rats and snakes frequently move. If Zhang's nest was built here, wouldn't it be similar to the wolf in the tiger's mouth? However, people may have snakes and rats in their homes, so when choosing nesting sites, swallows should consider not only the performance, but also whether these snakes and rats and other animals will invade them. Therefore, the places chosen by swallows are basically places where these small animals are difficult to climb. It must be said that with the protection of human beings, they are really protected from the threat of many natural enemies.
Third, but swallows are also very particular about choosing others to build nests. I believe many people have noticed that swallows generally grew up in rich or kind families after all. Because under normal circumstances, the quality of houses built by wealthy families will be better, which can not only protect the bird's nest from rain, but also improve the safety of the bird's nest to a certain extent, while the atmosphere of good families is often better and will not quarrel. Such a family can make swallows less disturbed and more conducive to reproduction.
Fourth, although there is a saying that swallows can look at Feng Shui, those low thatched huts are easy to leak and collapse when it rains, and cannot attract swallows to settle down. Therefore, people often mistakenly think that swallows are too poor to love the rich. Swallows will not change their nests easily without special circumstances, which is why they are so cautious about site selection. Swallows are migratory birds, and they will migrate with the change of seasons. Swallows who go back to their hometown after beginning of winter usually nest again with Chunni.