behavioral ecology = natural history + evolutionary theory


​Areas of Research:

Current Projects:

The evolution of cooperation 

 Cooperation between non-kin is a long-standing puzzle in evolutionary biology. Since cooperation typically involves some short-term fitness cost, it should be easily undermined by cheating and competition between group members. Our long-running research project in Panama focuses on the Greater Ani, a Neotropical cuckoo with an unusual breeding system. Whereas many cuckoos are specialized parasites which lay their eggs in the nests of other species, anis nest communally. Up to eight unrelated individuals construct a single nest in which all of the females lay their eggs, and all group members participate in incubation, defense, and food delivery to the shared clutch. However, reproductive competition within the group is intense: before laying her first egg, each female ejects any eggs that have already been laid in the communal nest. Each female stops ejecting eggs once she has laid her first egg, presumably to avoid accidentally removing her own. As a result, the first female to begin laying in the communal nest invariably loses at least one egg — sometimes several — whereas the last female to enter the laying sequence loses none. A main goal of this research is to quantify the reproductive costs and benefits to females of nesting communally.
Four unrelated Greater Anis (​Crotophaga major) simultaneously arrive at their communal nest bearing food for the mixed clutch of nestlings. Adults cannot recognize their own eggs or nestlings, so parental care is provided indiscriminately to the shared brood. © 2016 Christina Riehl.

Multi-level sociality

Palmchats (Dulus dominicus) are an endemic songbird native to Hispaniola (Haiti and the Dominican Republic) . Their large compound nests contain multiple nesting chambers used by different pairs and family groups 
​© 2023 Handbook of Birds of the World
Animals exhibit a stunning array of social organizations, from solitary living to complex hierarchical societies. Understanding the fitness tradeoffs that maintain this diversity remains a central challenge in evolutionary biology, yet most research on the origins and consequences of social behavior has focused on interactions within single social groups. Graduate student Qwahn Kent and postdoctoral research fellow Joshua LaPergola are bridging this gap by studying multilevel societies, complex social systems in which individuals cluster into groups, which are in turn clustered into larger social units within the population. Palmchats are a prime example: they breed in pairs or family groups, but several groups build a single compound nest (with separate chambers but a shared superstructure). Compound nests, in turn, are spatially clustered into loose neighborhoods. Qwahn and Josh are studying how birds move, communicate, and interact between these different tiers of social organization, and how cooperation and conflict shape these interactions.

Comparative analyses of reproductive traits

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Nest predation rates critically influence avian biodiversity, community ecology, and evolution of reproductive traits and breeding behavior. In the temperate zone, increased nest predation near edges and in forest fragments has been linked to declines and local extinctions of bird populations, and latitudinal differences in nest predation rates have been invoked to explain evolved trends in clutch size, development times, and other life history traits. However, we lack syntheses from tropical latitudes, where biodiversity is highest and increasingly threatened by habitat disturbance. Research affiliate (and former senior thesis student) Zach Smart is spearheading a collaborative project to provide the first global synthesis of nest predation rates across tropical and subtropical latitudes. With a network of international collaborators, we are building a comparative database of nest predation rates from over 1000 tropical sites.                                                                                                                                  
A Black Catbird (Melanoptila glabirostris) incubating on a nest in the Sian Ka'an Biosphere Reserve, Quintana Roo, Mexico. (c) Joshua LaPergola