What is the adaptive significance of microgeographic dialects?
My primary study organism is the little hermit (Phaethornis longuemareus), a rainforest hummingbird native to the Caribbean island nation of Trinidad. Males of this species form tightly-spaced groups (known as leks) to display for and attract females. Within a single lek (sometimes occupying only the area of a large swimming pool) males may form as many as six distinct song groups or dialects.
My dissertation work at Cornell focused on investigating both how and why these dialects form on such an unusually tiny spatial scale.
Why do males court females in the non-breeding season?
I am currently a member of the Webster lab at the Cornell Lab of Ornithology where I study the red-backed fairywren (pictured, left) in Queensland, Australia. Males of this species invest considerable time and effort to displaying to females other than their social mates during the non-breeding season, at a time when they have no chance of actually mating.
Why would males do this? Are females able to remember which males they have encountered over the many months of the non-breeding season? How do they know which males they have encountered? My current work focuses on answering these questions and discovering the functional significance of this unusual behavior.
Does vocal learning serve novel functions in lekking species?
Until very recently, it was generally accepted by the scientific community that the only birds capable of vocal learning were the oscine passerines (typical songbirds), parrots, and hummingbirds. However, intriguing evidence of vocal learning in other avian taxa has begun to surface, mainly in several lekking species, including the bearded bellbird (Procnias averano; pictured, left). Ongoing work in Trinidad seeks to find answers to how and why vocal learning appears to have evolved in bellbirds.
TRACKING TRAPLINERS: Using telemetry to find nests
A lekking male little hermit marked with a unique color-combination leg tag
A bright male red-backed fairywren performing a "puff back" display (photo by Joe Welklin)
An adult male bearded bellbird in Trinidad, showing off his curtain of black wattles
CURRENT PROJECTS
PAST PROJECTS
Why do females differ in their investment in mate searching?
An important driver of sexual selection is variation in mate choice across a population. For instance, if all females chose to mate with the same male, the opportunity for selection to operate would obviously be quite different from a scenario in which each female had a preference for a different male. One important reason we may observe variation in female choice of mates is an underlying difference in female investment in searching for mates (a.k.a. variation in choosiness), yet little work has explicitly sought to identify the factors that cause such variation in choosiness.
In collaboration with Dr. Emily DuVal at Florida State University, I sought to answer this question in a polygynous bird, the lance-tailed manakin. Check out Dr. Duval’s lab homepage for more information.
A male lance-tailed manakin