Why is it called evil cuckoo?

There is a legend about the cuckoo: in the beautiful heavenly palace, there was a kind and sensible girl who lost her parents when she was very young. Then I went to my aunt's house in Tiangong to help her take care of the children at home. A few years later, the girl's clothes began to get old and worn out day by day, so she asked her aunt for a pair of trousers to replace her tattered old trousers, but her aunt was cruel and stingy and refused to give her a better pair of trousers. The girl cried very sadly.

Aunt's children grew up day by day, and they didn't need the girl's care and care, so the cruel aunt ruthlessly drove the girl out of the house. This unfortunate and bitter child is crying sadly every day, quietly leaving this sad paradise and coming into this world, becoming a bird and crying "Aunt Pants" every day.

Cuckoo's cry is "Cuckoo … Cuckoo", which is somewhat similar, so it is extended that Cuckoo is a bad bird.