combining the skills of veterinary medicine and wildlife ecology. Revisiting this book after 15 years allowed me to consider changes at the interface between the two disciplines. Veterinary medicine traditionally has been concerned with the individual and with treating sick animals, while the ecologist is concerned with populations and the manager has limited interest in treating sick birds. During this period there has been a marked increase in awareness among veterinarians that they have a responsibility in wildlife and conservation biology. Curricula of many veterinary colleges now include material on non-domestic animals and attempt to put disease in an ecological context. Also during this time, waterfowl managers have become more aware of disease as a factor in population biology and there are early attempts to put numbers to "disease" in models of continental waterfowl populations.