ON THE WING

“About five billion land birds from five hundred species leave their North American nesting area to spend the winter farther south,” according to Lerner (My Indoor Garden, 1999, etc.), but that’s only part of the story told in this remarkable look at bird migration. The author here describes bird flight patterns North-South, East-West, and up and down from higher to lower altitudes with the changing seasons. She explains why some birds migrate all the time but others only some times, and why still others just stay home. Nearly every page has a helpful thumbnail map and a handsome painting of birds. Most intriguing are scientific studies about how birds prepare for migration, and how they find their way. For example, the tiny hummingbird adds 40 percent to his weight before migration, and can travel 500 miles nonstop. Lerner reports scientists have found “magnetite,” or lodestone, in the heads of homing pigeons, suggesting they have a built-in magnetic compass. Other studies show caged birds with a pattern of the northern sky on the ceiling attempt to fly in their migratory path. If some stars are removed, the bird still flies in the correct direction, but if all stars are removed, the bird is confused and flutters in all directions. The author concludes with suggestions on birdwatching, groups, and guidebooks. This is super science, beautifully presented. (index) (Nonfiction. 9-11)