"And how they decide where to stop and build their nests," said Mrs. Leonard. [Illustration: Oriole.] "Very interesting questions, but no one has answered them yet," said Uncle Robert. "Migrating birds are all found in the south in winter, and we see them in the spring." "What do you mean by mi-grat-ing birds?" asked Susie. "Birds that fly from one part of the country to another," said Uncle Robert. "The bluebird is the first to come," said Donald. "A patch of blue sky," said Uncle Robert. "You forget the geese that screech over our heads in the early spring," said Frank. "They fly in flocks shaped like an arrow." [Illustration: Bluebird.] "The 'bobwhite' is the funniest little bird. One comes right up to my garden fence. It is a shame to shoot them!" said Susie. "It is a shame to kill any bird unless you need it for food. Every time a bird is killed the farmer loses one of his best helpers. The birds work for the farmer from morning to night." "Oh, now you are making fun, Uncle Robert," said Susie. "The birds don't work at all. They just fly around and have a good time." "The crows don't work for the farmer when they pull up his corn," said Frank. "Nor the hawks when they steal his chickens," added Mr. Leonard. "The cherry birds steal the cherries, and the sparrows eat the strawberries," said Susie. "You would soon find out how much the birds do if they should all fly away," said Uncle Robert. [Illustration: Crow. ] "The cankerworms would eat the leaves of the apple and other trees, and insects of all kinds would destroy the crops. The crow taxes the corn in payment for all the good he does. The hawks eat a thousand mice to one chicken--in fact, very few hawks eat chickens, anyway. The cherry birds and sparrows should be allowed a little toll for all the fruit they save. I want you to read a charming book called The Great World's Farm. The author calls birds 'Nature's militia.' The morning song of the birds means 'We are going to help the farmer to-day.'" "That's true," said Mr. Leonard. "The farmers are just learning what a help the birds are to them. We have found that they eat the grubs, the worms, and the bugs before they eat everything else." "Would there be very many more worms than there are now," asked Susie, "if the birds should go away?" "You don't remember, do you, Susie," said her mother, "how many caterpillars there were in the village the year they tried to drive the sparrows away?" "I do," said Donald. "Wasn't it dreadful? Why, Uncle Robert, the leaves were all eaten off the trees, and you could hardly take a step without squashing a caterpillar." "Ugh!" said Susie with a shudder. "I'm glad I was too little to remember it." "But the strange part of it was," said Frank, "that out here we hardly saw a caterpillar all summer." "And our trees were never more beautiful," said Mrs. Leonard. "Perhaps the village sparrows came to visit you," said Uncle Robert.