Lab Members

Christina Riehl,
Associate Professor

Office: Briger A363
email: [email protected]
​Click here for CV
Christie studies the ecology and evolution of avian life histories, especially in tropical species. Her long-term research project is on cooperatively breeding greater anis in Panama, with many other projects on the evolution of parental care and mating systems in birds. She is also affiliated with the Smithsonian Tropical Research Institute, Princeton's High Meadows Environmental Institute, and Princeton's Program in Latin American Studies. Her Google Scholar page is here.

Joshua LaPergola,
Postdoctoral Researcher

Office: Briger A361
email: [email protected]
Twitter: @DoctorScience7
​Josh studies the behavior and natural history of tropical birds and the ecology and evolution of sociality. His current postdoc project focuses on collective decision-making in greater anis and using double-digest RAD sequencing to understand kinship patterns in several tropical bird species. Josh earned his M.S. at Villanova University and his Ph.D. at Cornell University, where he studied coloniality in the Hispaniolan Woodpecker. In his spare time, Josh shares his love of nature with his son and daughter, attempts to ensure their survival to adulthood, and dabbles in painting and drawing. Check out his website here.

Cynthia Ursino,
Postdoctoral Researcher

Office: Briger A361
email: [email protected]

Cynthia studies the ecology and evolution of bird behavior, with a focus on mating systems, brood parasitism, ecto-parasitism, cooperative behavior, and parental care. As a Presidential Postdoctoral Fellow in the Riehl Lab at Princeton University, she explored whether ecological pressures can favor the evolution of social and genetic monogamy in species lacking parental care. In addition, Cynthia investigates species with cooperative breeding systems, which present contrasting social structures. This cooperative behavior can shape both social and genetic mating systems, ultimately influencing fitness at the individual and group levels.
She received her Ph.D. from the Universidad de Buenos Aires, Argentina, where she studied the evolution of host-parasite interactions between the specialist Screaming Cowbird and its primary host, the Baywing. Her Google Scholar page is here, and her website is here.

Elisa Yang,
Ph.D. student

Office: Briger A361
email: [email protected]
Elisa joined the Riehl lab in the fall of 2023 after completing a B.S. in environmental science at UC Berkeley. As an undergraduate, Elisa studied the comparative phylogenetics of estrildid finches with whole genome data. She hopes to continue her research in bird evolution, using tools from behavioral ecology and genetics to study avian systems with unusual life histories. 

Qwahn Kent,
Ph.D. student

Office: Briger A361
email: [email protected]
Qwahn joined the Riehl lab in the fall of 2022 after completing a B.S. in Biological Sciences at Cornell University. During his undergrad, Qwahn studied avian community composition and biogeography patterns in the Northwest Himalaya. His Ph.D. work focuses on understanding the social dynamics of cooperatively breeding Palmchats (Dulus dominicus) in the Dominican Republic.
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Bre Bennett,
Ph.D. student

Office: Briger A361
email: [email protected]
Bre joined the Riehl lab in 2021 after receiving a B.S. from Villanova University and subsequently conducting field work on Black-capped and Carolina Chickadees in the Curry lab. Bre's Ph.D. work focuses on breeding behavior and conservation of Black Vultures (Coragyps atratus) in Pennsylvania, in collaboration with Hawk Mountain.

Bridget Harrington,
​Ph.D. student

Office: Briger A361
Email: [email protected]
​Bridget joined the Riehl lab in the fall of 2025 after completing a master's in Biology at the University of Oxford. During her master's, Bridget investigated dual foraging in Manx Shearwaters, and is excited to start exploring cooperative breeding for her PhD!

Sam Hagler, 
Ph.D. student

Office: Briger A361
Email: [email protected]
Sam joined the Riehl Lab in 2025. She received her B.S. in Biological Sciences from Cornell University in 2020, where she studied the behavioral ecology of passerines (red-backed fairywrens) and raptors (cooperatively breeding Harris's Hawks). Sam also has experience in museum collections, as a bird bander, and as a falconer! For her PhD, she is interested in studying cooperation in birds between non-kin, and the environmental drivers of social behavior.

Solomon (Sully) Williams, 
Senior thesis student

Office: Briger A361
Email: [email protected]
Sully Williams '26 is an undergraduate EEB major conducting senior thesis research in the Riehl lab. In 2025 he completed field research with Qwahn Kent on the vocalizations and social relationships of cooperatively breeding Palmchats in the Dominican Republic. Sully's senior thesis will investigate if the Palmchat's unusual communal nesting influences willingness to participate in cooperative behaviors. He is also a member of the varsity football team, the founder & president of the Princeton Varsity Athlete Premedical Society, and will attend the Icahn School of Medicine at Mount Sinai after graduation.

Xiaotong (Mint) Ren,  
​Ph.D. student

Mint began her Ph.D. research in 2024 in the Wilcove lab and is also affiliated with the Riehl lab. She is an ecologist and conservationist with a general interest in understanding and conserving birds and their habitats, from mudflats to mountains. Prior to Princeton, she completed her BSc at Fudan University, China and MSc at the University of Queensland, Australia studying migratory shorebird ecology and conservation at both flyway and global scales. She is also an avid birdwatcher and a semi-professional soccer player.

Jessica Wang,
Undergraduate intern

Jessica Wang '26 is an undergraduate EEB major who joined the Riehl lab in 2024. She conducted field work on greater anis in Panama, where she worked on local ani population monitoring and decision-making experiments as a research assistant on Barro Colorado Island. On campus, she advises students as a Writing Fellow and sings in the Princeton Playhouse Choir. Watch the amazing video that Jessica made about referential calling in greater anis, which won a Princeton Research Day award, here.

Paige Landry,
Senior Thesis student

Paige Landry '25 is an undergraduate EEB major conducting senior thesis research in the Riehl lab. In 2024 she completed field research on vocalizations and behavior of cooperatively breeding Palmchats in the Dominican Republic, mentored by Qwahn and Josh. Paige's senior thesis will provide the first description of the Palmchat vocal repertoire. She also works as the Director of Procurement for the Coffee Club, Princeton's student-run coffee shop. 

Lab Alums

Dr. Fengyi (Freda) Guo

Freda received her Ph.D. in 2024  in the Wilcove lab and was also mentored by the Riehl lab. As a conservation ecologist, her dissertation focused on the stopover ecology and conservation of migratory landbirds in North America. Combining data-driven radar aeroecology and on-the-ground field surveys, she aims to identify stopover hotspots and key habitats for migratory landbirds during the en-route period, thus completing the full-annual-cycle conservation of migratory species. Freda is now moving to Cornell's Lab of Ornithology to begin a Rose Postdoctoral Fellowship! Her Google Scholar page can be found here. ​

Dr. Severine Hex

Severine received her Ph.D. in 2024 and was co-advised by the Rubenstein and Riehl labs. She is interested in the ecology and evolution of animal communication, including the relationship between communicative and social complexity. Her Ph.D. research focused on multimodal communication and social complexity in equids, particularly the plains zebra. Severine is now beginning a postdoctoral appointment at the University of Maryland, studying communication and social behavior in bats!
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Dr. Amanda Savagian

Amanda received her Ph.D. in 2022. Her dissertation research focused on the evolution of vocal communication in communally breeding groups of greater anis; how begging signals evolve in groups composed of mixed kin and non-kin; and how patterns of resource allocation to nestlings change with group size and composition. Amanda is currently an environmental analyst for Cascadia Consulting!​

Dr. Maria Smith

Maria received her Ph.D. in 2023. Her dissertation research focused on the division of labor and workload in communally breeding groups of greater anis in Panama. Her work revealed that social group stability affects the frequency of reproduction; that inequality in workload increases with group size; and that  individual anis do not specialize on particular tasks. A black-belt birder and ornithologist, Maria is now the Managing Editor for the Birds of the World project at the Cornell Laboratory of Ornithology!

Dr. Daniel Baldassarre

Dan is now Associate Professor of Ornithology at SUNY Oswego. His postdoctoral project in the Riehl lab focused on the phainopepla, a passerine thought to be an itinerant breeder. Using a combination of GPS tracking and phylogeography, Dan confirmed that individuals move between two distinct breeding areas with an "extra" migratory movement in between. His research paper was the cover article for the Auk (here), and you can watch a YouTube video that tells this amazing story (here).
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  Zach Smart '19

Zach is now a graduate of the M.S. program in social work at Columbia University. His undergraduate senior thesis work at Princeton focused on effects of climate in greater anis, for which he conducted field work in Panama for 3 summers.  Most recently, Zach led a large meta-analysis on nest predation rates in tropical birds with the Riehl lab and a network of international collaborators.
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