When you look out your window, why are you so much more likely to see a robin or a sparrow than a Kirtland's warbler or a California condor? Why are some animals naturally rare and others so abundant? The quest to find and study seldom-seen jaguars and flamboyant Andean cocks-of-the-rock is as alluring to naturalists as it is vitally important to science. From the Himalayan slopes of Bhutan to the most isolated mountain ranges of New Guinea, The...