David has been an avid birder for over 25 years, during which time he has worked on field research projects in Borneo, Peru, Central America, and every western state. As a professional naturalist he has led hundreds of birding tours, classes, and programs, many of these in the last 3 years with his partner Simone Whitecloud. David is also the author of Wild Birds of California, Watchable Birds of the Great Basin, and the newly revised Sierra Nevada Natural History, as well as many magazine articles. His weekly column Field Guide appears in the Los Angeles Times newspaper.