Nepal's extraordinary vertical geography packs a planet's worth of avian life into a single journey from tropical wetlands to the high Himalaya. BY RICHARD F. SILBER · EXECUTIVE DIRECTOR, INTERNATIONAL MOUNTAIN TREKKING The male Himalayan Monal — Lophophorus impejanus — Nepal's national bird, and arguably the most spectacular pheasant on Earth. There is a moment, somewhere above 3,000 meters in Nepal's Khumbu Valley, when the forest thins and the rhododendrons give way to open alpine meadow,...