My research focuses on developing an interdisciplinary field that might best be termed “Behavioral Community Ecology”. The aims of this field are to investigate how behavioral interactions between members of the same trophic level, broadly categorized, influence the distribution of animals in space and time. Generally, I view such behavior as a potential form of facilitation between species, which may act as an opposing force to competition. I am especially interested in how interspecific information transfer influences animal communities (see Goodale et al., TREE, 2010).
Questions that are addressed in this field include the following: What do animals learn from members of other species, and what effect does this information flow have on the distribution of species, and the composition of communities? Are there certain systems of information flow that are more stable than others? Under what conditions is this information flow parasitic (flowing in one direction), as opposed to mutualistic (bi or multi directional)? What species play especially important roles as information sources for communities, and can such ‘nuclear’ or ‘keystone’ species be targeted in conservation plans?
In searching for answers to these questions, I have primarily studied communication in mixed-species flocks of birds. Mixed species flocks are found throughout the world, and present a unique opportunity for community ecologists: flocks are discrete (every birds is either inside or outside a flock), easily observable communities. The goal of research on mixed-species flocks is clear: given a list of the birds in an area, and some particular characteristics of these species, can we predict which species are in flocks, and which species are nuclear species for the flocks? I believe we can, and I think that the information encoded in vocal signals is one of the primary factors that drives the structure of these communities.
My thesis work at the University of Massachusetts, Amherst, advised by Bruce Byers and Don Kroodsma, focused on vocal communication among members of a mixed-species flock system. In particular, I studied how information about predators is passed in alarm vocalizations through the flock system and how one species manipulates other birds through vocal imitation. My thesis work was supported by pre-doctoral and DDIG grants from NSF, and all seven chapters have now been published. Accomplishments of this research include (also see summary article in Natural History, 2008):
1) The first community wide study of alarm calling and response to alarms in tropical mixed-species flocks (Auk, 2005; Behavioral Ecology 2008).
2) A novel playback technique for measuring species roles in mixed-species communities (Journal of Tropical Biology, 2005)
3) The first demonstration of context-dependent mimicry in a bird (Proceedings of the Royal Society, 2006).
4) A demonstration that vocal mimicry can be used to manipulate other species (Animal Behaviour, 2006)
In my postdoctoral experience, I have widened my perspectives geographically, taxonomically and thematically. A NSF International Research Postdoctoral Fellowship supported 16 months of field work in Sri Lanka on the development of vocal mimicry and 8 months of field work in Papua New Guinea (PNG) on the function of vocal mimicry in a flock system where some participants contain toxins in their feathers. In Sri Lanka and India, I simultaneously ran a conservation oriented project which aimed to understand how flocks are affected by human land-use, through a large scale flock sampling effort funded by the Conservation, Food and Health Foundation. I have also had postdoctoral experience in North America: a postdoctoral fellowship at the MIT Media Lab with Dale Joaquim focused on conducting remote playback through cell phone technology, and with Mark Ashton at the Yale School Forests I studied the effect of active forest management on bird populations. Accomplishments from this work include:
1) A preliminary report on the utility of cellular telephony for listening to and interacting with animals (Biology Letters, 2007).
2) A two year survey of the Yale-Myers Forest, focusing on how regeneration cuts and stand improvement techniques combine to affect the abundances and distributions of birds (Forest Ecology and Management, 2009)
3) A review article of Asian bird flock systems, the first summary of these communities for the Old World tropics (Current Science, 2009).
4) A review article on leadership of mixed-species bird flocks with Guy Beauchamp (Journal of Avian Biology, 2010).
5) Review articles on the role of interspecific information transfer in shaping animal communities (TREE, 2010, and the Encyclopedia of Animal Behavior, in press)
6) Collaborations with Sri Lankan students on false alarm calling in mixed-species flocks (Behavioral Ecology 2010) and the sharing of raptor imitation by several species (Naturwissenschaften 2010).
In addition to this completed work, data has been collected on several projects, including: the impact of land-use on mixed-species flocks in India and Sri Lanka; the association patterns between species in the same dataset, and the development of novel statistical techniques for detecting these; the change in vocal mimicry over a breeding period and the development of mimicry in free-living birds in Sri Lanka; the connection between mimicry and toxicity in flocks in PNG; and the effect of land-use, especially shifting agriculture, on birds of PNG generally.
Currently, I am starting a project investigating how dominance hierarchies shape interspecific information transfer among pollinating insects, in collaboration with the lab of James Nieh at the University of California, San Diego. I am excited to extend my research into a new taxon, and one that is more easily manipulated in experiments than birds. In the future, I hope to keep interspecific communication as the central theme around which studies will be carried out in a range of taxa, in both the field and in the lab.