David received his Ph.D. in Evolutionary Biology in August 2012.
Current Position: Postdoctoral Researcher, Uppsala University, Sweden
I am interested in the evolution of cooperation involving unrelated individuals, which has presented a problem for evolutionary biology since the 1960s. The principle difficulty is that animals engaging in cooperative behaviors benefit others, but might themselves experience costs. Although theoretical solutions to this problem have been proposed, their relative importance in the natural world and the evolution of the proximate mechanisms that facilitate them is poorly understood. I work on a cooperative anti-predator behavior that birds use to drive threatening predators away, called mobbing, at two communities of breeding birds in the Indian Himalayas. Mobbing can benefit birds, because predators are sometimes driven away, but participation is costly, because predators sometimes eat mobbers. Mobbing displays, called “mobs,” are often composed of individuals from multiple species. My goal is to evaluate how mobbers benefit from their actions and how individuals from multiple species communicate to form mobs. I use presentations of taxidermied predators and playback recordings of the vocalizations that birds make during mobs to analyze when and how mobs form.