The Salton Sea spreads across a remote valley in California's lower Colorado Desert, 40 miles (65 kilometers) from the Mexican border. For birds migrating along the Pacific coast, it's an avian Grand Central Station. In midwinter tens of thousands of snow geese, ducks, pelicans, gulls and other species forage on and around the lake. Hundreds of other species nest there year-round or use it as a rest stop during spring and fall migration.