A recent study by the Nature Conservancy confirms that thinning of forests here in the Southwest is good for trees and the wildlife sustained by them, including birds. An Audubon sponsored project involving scores of scientists has come up with a new way to track birds in migration. A report on how dressing for desert conditions, especially in the heat of summer, is critically important. Bird of the episode: Lucy's Warbler. Birding hotspot: Chevelon Canyon Wildlife Area. Friend of wildlife: Arizona Conservation Corps.