PigeonWatch is an international research project that involves people of all ages and locations. PigeonWatch participants observe pigeons and send their data to the Cornell Lab of Ornithology, where scientists compile the information and use it to examine two questions of scientific interest: 1. why pigeons continue to exist in so many colors and 2. which color morphs pigeons prefer for mates. People participate by counting pigeons and recording the colors of courting pigeons observed in their neighborhood pigeon flocks.   It combines real hands-on science with neighborhood-based education. PigeonWatchers learn about birds, behavior, and how science and scientists work.