Stuart Pimm couldn't imagine studying nature without being involved in saving it. Now a professor of conservation biology at Duke University, he is an expert in mass extinction. As a teenager, he loved watching birds. To pursue his passion for ornithology, he went to Oxford, and later to New Mexico State University, where he earned his Ph.D. Then he went to Hawaii in the late 1970s, for a six-month period of fieldwork, where he wanted to see all the bird species that were supposed t