The concept for this volume began as a scientifi c symposium at the North American Ornithological Conference (NAOC) in Veracruz, Mexico in October 2006. The symposium was entitled “Avian Distributional Change, Anthropogenic Challenges, and Recent Avian Research and Technological Advances within the US–Mexico Border Region,” and was cochaired by two of us (DJK and TB) along with Carol Beardmore (Sonoran Joint Venture) and Bill Howe (USDI Fish and Wildlife Service). In light of the importance of the borderland region for birds and bird conservation, and because of the great need for additional information about this poorly studied region, we have compiled this volume to present new information about bird distribution, ecology, and conservation.