Beth Youngby, age 10, of Sioux City, Iowa, for her question:

Do they know how homing pigeons find their way home?

The Egyptians learned to train homing pigeons, some 3,000 years ago. Ever since then, mankind has been baffled by how these birds find their way home from strange, faraway places. Modern researchers can suggest only a couple of ideas. Some suspect that these and perhaps other birds are sensitive to the earth's magnetic field and use its variations to chart their courses. Some suspect that they navigate by beams from the sun and stars. We know that homers recognize local landmarks and use them to chart short journeys.

However, their longer navigation feats are fantastic. We know that they can fly 1,000 miles in two days    which must mean flying straight home, with no miscalculations or wrong turns. We don't know how they do it, but we have a good idea why. The homer is a most affectionate bird, deeply devoted to his family. When Mr. Homer returns home, he can't wait to shower Mrs. Homer with tender loving coos and kisses.