Dr. Riehl studies the evolution of social behavior, particularly the evolution of cooperative breeding in birds, using a combination of methods including behavioral observations, molecular genotyping, and field experiments to determine the reproductive fitness of individuals in cooperatively breeding groups. She is also interested in brood parasitic life-history tactics, and the co-evolution of behaviors of avian brood parasites and their hosts, particularly in the Neotropics, with field sites in Colombia and Panama (in collaboration with the Smithsonian Tropical Research Institute).