Bruce Lyon is a professor of Evolutionary Ecology at the University of California, Santa Cruz. His research focuses on the evolution of reproductive strategies and mating behavior of birds. His long-term research on the adaptive basis of brood parasitism in several waterbirds has sought to understand why parasitism within species evolves and how the behavior influences other aspects of social behavior. Bruce has also investigated the evolution of ornamental plumage signals in a variety of bird species. Most recently he has conducted a 15-year investigation into the winter social lives of migrant golden-crowned sparrows. In the talk, Bruce will discuss findings from the long-term study of brood parasitism in the American coot, a waterbird that is common throughout western North America. He will discuss the basic natural history of parental care and brood parasitism in this intriguing species, and will then discuss ecological and cognitive aspects of two defenses hosts use to reduce the costs of brood parasitism, egg rejection and chick rejection.