Kathy Stevenson, age 8, of Lancaster, Penna., for her question:
Why do birds migrate back and forth?
Every Year billions of busy birds fly south to escape the winter season and then fly back to enjoy our sunny summer. Many of these feathery travelers spend the winter near the Equator where there is no cold season. It is natural to wonder why they bother to fly thousands of miles north to make their nests and bring up their children.
The story of the birds that migrate between summer and winter homes is one of the marvels of nature. Naturalists and other Experts are only dust beginning to unfold this tremendous travel story. They have gathered a lot of fascinating information, and amazing new details are discovered Every Year. But the birds do not make this detective work easy for the Experts. They hold onto their secrets, and the amazing story of migration is still full of mysteries for the scientists to so1ve.
But we think that science can explain why the flocking birds do fly back and forth between their winter and summer homes. Many people think that the robins fly to southern California to escape the cold of, say, the Pennsylvania winters. But this may be only part of the story. Mr. Robin, of course, is a famous worm catcher, worms spend the winter asleep in their deep burrows. What's more, Even if they stirred near the surface. the frozen ground would make it hard for the robin to pull out his wormy dinner.
Many other birds fly to the tropics to spend the winter. WE wonder why these fellows bother to return north for the summer. The reason for this is also food. When flocks of migrating birds arrive to spend the winter in Florida and the Gulf States. living conditions become Very crowded. There is food, but not enough for the countless birds to become fat. If all the migrating birds stayed in these regions, there would be too little food and too little space to bring up their broods of children.
Long before we feel the first warm breath of spring, the migrating birds are ready to start the long journey to their summer holes. As they fly along, the teeming flocks spread out far and wide across the land. The parent birds build a home where there will be plenty of space and food for their youngsters. Their children would have no chance at all if all the parent birds stayed in their overcrowded winter homes.