Dr. Christina Riehl • Cheaters and Collaborators December • November 2024

Cuckoos are famous for their parasitic laying habits, but not all cuckoos are parasites. The Greater Ani, a tropical cuckoo, nests in communal groups composed of several unrelated pairs. Each group builds a single nest and jointly provides parental care to the mixed clutch of young. Adults cannot recognize their own eggs or nestlings, and parental care is shared more or less equally by all group members. Greater Anis are long-lived and do not migrate, and these social groups can remain together for years - even decades. Despite these cooperative behaviors, females can also act as parasites, laying eggs into the nests of other groups and failing to provide parental care. Why, and how, do such groups form? Why do females sometimes act as parasites, and how do group members defend their nests against parasitism? Finally, how do group members synchronize their reproduction and coordinate parental care? In this talk, Christina Riehl will present findings from her long-running field project in Panama, which aims to understand the ecology and evolution of this unusual breeding system.
Christina Riehl is an Associate Professor in Ecology and Evolutionary Biology at Princeton University. Her research focuses on the evolution of avian life history and reproductive biology, especially social behavior, mating systems, and parental care. She is particularly interested in tropical birds, which exhibit a greater diversity of breeding behaviors than their temperate-zone counterparts and remain comparatively under-studied. Christina is a Fellow of the American Ornithological Society and serves as the Editor-in-Chief of the journal Ornithology. She received her Ph.D. from Princeton University in 2011 and completed postdoctoral fellowships at the Smithsonian Tropical Research Institute and at the Harvard Society of Fellows before returning to Princeton as a faculty member in 2015.