Joel Greenberg is a research associate of the Chicago Academy of Sciences Peggy Notebaert Nature Museum and the Field Museum. Author of three books, including A Natural History of the Chicago Region, Greenberg has taught natural history courses for the Morton Arboretum, Brookfield Zoo, and Chicago Botanic Garden. He helped spearhead Project Passenger Pigeon to focus attention on human-caused extinctions. Greenberg lives in Westmont, Illinois. Visit his blog at Birdzilla.com.