Why does the cuckoo call "cuckoo"?

The Story of the Little Boy and the Wicked Step-mother.

ONCE upon a time there was a poor man, who had a wife and two children, a boy and a girl. He was so poor that he possessed nothing in the world but the ashes on his hearth. His wife died, and after a time he married another woman, who was cantankerous and bad-natured, and from morning till evening, as long as the day lasted, she gave the poor man no peace, but snarled and shouted at him. The woman said to him, "Do away with these children. You cannot even keep me, how then can you keep all these mouths?" for was she not a step-mother? The poor man stood her nagging for a long time, but then, one night, she quarrelled so much that he promised her that he would take the children into the forest and leave them there. The two children were sitting in the corner but held their peace and heard all that was going on.

               The next day, the man, taking his axe upon his shoulder, called to the children and said to them, "Come with me into the forest, I am going to cut wood." The little children went with him, but before they left, the little girl filled her pocket with ashes from the hearth, and as she walked along she dropped little bits of coal the way they went. After a time they reached a very dense part of the forest, where they could not see their way any longer, and there the man said to the children, "Wait here for a while, I am only going to cut wood yonder, when I have done I will come back and fetch you home," and leaving the children there in the thicket he went away, heavy hearted, and returned home. The children waited for a while, and seeing that their father did not return, the girl knew what he had done. So they slept through the night in the forest, and the next morning, taking her brother by the hand, she followed the trace of the ashes which she had left on the road, and thus came home to their own house. When the step-mother saw them, she did not know what to do with herself, she went almost out of her mind with fury. If she could, she would have swallowed them in a spoonful of water, so furious was she. The husband, who was a weakling, tried to pacify her, and to endeavour to get the children away by one means or another, but did not succeed. When the step-mother found that she could not do anything through her husband, she made up her mind that she herself would get rid of them. So one morning, when her husband had gone away, she took the little boy, and without saying anything to anybody, she killed him and gave him to his sister to cut him up, and prepare a meal for all of them. What was she to do? If she was not to be killed like her brother, she had to do what her step-mother told her.

               And so she cut him up and cooked him ready for the meal. But she took the heart, and hid it away in a hollow of a tree. When the step-mother asked her where the heart was, she said that a dog had come and taken it away. In the evening, when the husband came home, she brought the broth with the meat for the husband to eat, and she sat down and ate of it and so did the husband, not knowing that he was eating the flesh of his child. The little girl refused to eat it. She would not touch it. After they had finished, she gathered up all the little bones and hid them in the hollow of the tree where she had put the heart. The next morning, out of that hollow of the tree there came a little bird with dark feathers, and sitting on the branch of a tree, began to sing, "Cuckoo! My sister has cooked me, and my father has eaten me, but I am now a cuckoo and safe from my step-mother." When the step-mother, who happened to be near the tree, heard what that little bird was singing, in her fury and fright she took a heavy lump of salt which lay near at hand, and threw it at the cuckoo, but instead of hitting it, the lump fell down on her head and killed her on the spot. And the little boy has remained a cuckoo to this very day.