这是一个童话故事，但自然界里的有一些种类的杜鹃鸟，真的像故事里说的那样，自己不做巢，不孵蛋，而是把蛋下在其他鸟的巢里。不过，对于人类来说，杜鹃却很有用。有些森林的害虫别的鸟不敢吃，杜鹃却特别爱吃，它是著名的保护森林的益鸟呢。

This is a fairy tale, but there are some species of cuckoo birds in nature. As the story says, they do not make their own nests or hatch their eggs, but lay their eggs in the nests of other birds. For humans, however, cuckoos are useful. It is a famous bird that eats insects and protects the forest.