Laura Beaumont, age 12, of Milwaukee, Wis. for her question:

WHY DON’T THE BIRDS STAY SOUTH IN THE SUMMER?

The birds flock south to escape the cold and also to find seeds and insects. But their winter quarters are rather crowded, with barely enough food for them all. Come spring the parent birds make plans for the nesting season. They fly back home in time to feast on new plant growth and newly hatched insects. Here they also can spread out, and each family claims enough territory to provide food for the hungry chicks.