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 study communication in mixed-species flocks of birds. ‘Birds of many feathers flock together’ throughout the world, and such flocks 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 or nuclear species for the flocks? I believe we can, and I think that the vocal characteristics of species, and the information encoded in vocal signals, is one of the primary factors that drives the structure of these communities. For an annotated bibliography on mixed-species bird flocks, click here.

My thesis work at the University of Massachusetts, Amherst, advised by Don Kroodsma and Bruce Byers, 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 both geographically and thematically.  With the Sri Lankan system, I have gone in a developmental direction, studying how birds learn how to mimic. A NSF International Research Postdoc has also supported a field study of mixed-species flocks of Papua New Guinea where some flocks participants contain toxins in their feathers.  In Sri Lanka and India, I am simultaneously running a conservation oriented project which aims 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 the U.S: 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. Highlights of this on-going work include:

1. A preliminary report of the utility of cellular telephony in listening to and interacting with animals of the MIT Media Lab (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 flock systems, the first summary of these communities for the Old World tropics (article with 9 co-authors, Current Science 2009).
4. A review article on leadership of mixed-species flocks with Guy Beauchamp (Journal of Avian Biology, in press).
5. The development of a statistical framework for detecting species associations from multi-site community composition data (in collaboration with Emily Silverman of US Fish and Wildlife), and empirical tests of these models (in collaboration with Sarath Kotagama in Sri Lanka, and T. R. S. Raman in India).
6. Demonstration that birds can have different development tracks in learning alarm calls, as opposed to other classes of vocalizations, and in learning mimicry, as opposed to species-typical vocalizations.  This data, still being collected, will have important implications for our understanding of how birds learn to vocalize.
7. A playback experiment in Papua New Guinea that tests whether birds preferentially join other species that are toxic (data still in collection).
8. A synthesis of the role information transfer between species plays in animal communities (in preparation for TREE). 
   

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