What is that funny-looking flying machine, and what's it doing with those birds? It's an ultralight plane, and it's leading a flock of young whooping cranes on a migration route from Wisconsin to Florida. Why? It's just one small part "of an enormous...

Stately in their scarlet crowns and long tails of silvery-gray feathers, a group of Mississippi sandhill cranes crunches across winter grasses at the Mississippi Sandhill Crane National Wildlife Refuge near Biloxi. Their long, sticklike legs carry bangles of green and sometimes red. These...