"Oh, Father, you aren't going to cut the grass now, are you?" said Bobby. "Yes," said Father, "the clover is ready." "I wish it could be left all Summer," said Bobby. "But we must cut it," said Farmer Hill, "to make hay for the horses and cows to eat next Winter." When the mower was ready, they hitched Prince and Daisy to it, and Father climbed to the seat and drove to the hayfield. As the mower went around the field, it cut a wide swath of clover and left it lying flat on the ground. A humming sound the mower made, a pleasant sound to a person some distance away, a very loud sound to one near by. In one of the nests in the field, there was a mother bird and three young birds. The little mother bird, there in the quiet clover field, had never heard such a loud sound before. "What can it be that makes that big noise?" the frightened mother bird thought as the mower passed close by. Then the sound grew fainter as the mower went to the other side of the field. The little mother bird settled down happily in her nest. But it was not long before the sound came back again, closer and louder than before. "What shall I do?" thought the mother bird. "What shall I do?" She might have flown away herself. But there were the three young birds not yet old enough to fly. So she sat still while the terrible noise kept coming nearer. All this time, Bobby was playing here and there with Rover. Suddenly, Bobby thought of something. He ran toward the mowing-machine, waving his hands and shouting. "Stop, Father, stop!" he said. The mower made such a loud noise that Father could not hear what Bobby was saying, but he could see his arms waving. "Whoa, Prince! Whoa, Daisy!" he said, and the horses stopped. "What is the matter, Bobby?" he asked. [Illustration: "'Stop, Father, stop!' he said"] "The bird's-nest! There's a nest right ahead," shouted Bobby. "A bird's-nest, is there?" said Father. "Well, we won't harm the nest. Go and stand near it, Bobby, and I'll turn out for it." Bobby hunted around until he found it in the clover. Then he took his stand beside it. Father clucked to the horses. "Get-up, Prince! Get-up, Daisy!" he said. When he came near Bobby, he turned out and passed a few feet away, leaving the nest all safe. Bobby stood there until Father went around the field and came back again, so that the wheels of the mower would not run over the nest or the horses step on it when passing on the other side. "Are there any more nests in the field?" asked Father. "There is one at that end," said Bobby, pointing toward the west; "and one down there," pointing toward the east. "If you will set a tall stick in the ground near each one," said Mr. Hill, "I can see where the nests are, and you won't have to stand there." "All right," said Bobby, and he started toward the house for the sticks. As he was hunting for them, he remembered his little flags that always stood in the corner of the parlor.