What is there to love and care for swallows? Please grasp the key sentences and type them.

Swallows are birds that are beneficial to human beings. They mainly feed on insects such as mosquitoes and flies. They can eat up to 250,000 insects in a few months and "return them at this time of year". As early as thousands of years ago, people knew the law of swallows flying back to autumn and spring.

According to legend, in the Spring and Autumn Period, a maid-in-waiting once cut off the foot of a swallow in the Wu Palace to see if it would fly back to its original place next year. Coincidentally, a man named Fu Xian in the Jin Dynasty also observed this way. As a result, the swallow without claws came back the next spring.

Swallows usually fly at night, especially when the moon is bright and windy, and rest on the ground for food during the day. Moved by the flying habits of swallows, ancient poets once described it as "Pharaoh flies away before he dies" and "the flowers fall and the swallows return when they are ripe".

Since ancient times, people have been happy to let swallows nest and have children at home, which is considered a blessing. Although the ground under the bird's nest is often dirty, people don't mind. Swallows are seasonal migratory birds. People call it "Spring Swallow" and "Flying Swallow". Seeing swallows seems to remind people that spring is coming!

Extended data:

Domestic swallows have a "quirk": they always fly in the dead of night, with the moon hanging in the sky and flying very fast. Sometimes they can only see their own shadow passing by, but they can't see it.

Swallows also have amazing memories. No matter how far they have gone, even across the Qian Shan, they can rely on amazing memories to return to their hometown. Like many other animals, swallows have unparalleled perception. One of the most striking is the ability to tell the direction. Someone did an experiment. He caught seven swallows in a German city, drew a sign, and then flew to England to set them free. The next morning, five of the seven swallows returned to their nests in Germany.

References:

Baidu Encyclopedia-Yan (passeriformes, Yanidae)