Swift is a summer migratory bird that migrates to North China in mid-April every spring. Baoding city is generally 15, with a difference of no more than two days. At this time, around Grain Rain, the ground temperature began to rise continuously, bloom was warm in spring, insects came back, and Swift had more food. The temperature is neither too high nor too low, and the average temperature is around 15 degrees, which is a good season for swift breeding. At the beginning of May, swift began to mate, and we will make a further detailed observation on the reproduction of swift. At the end of July, when Swift was mature enough to fly alone for food, the family moved south and will revisit their hometown until next spring.