February 25, 2009

Bird behavior explained by ‘game theory’

British and Norwegian scientists say they've used game theory to explain the strange behavior of ravens observed foraging for food in gangs.

The scientists, led by Sasha Dall at the University of Exeter, said it's the first time game theory -- a mathematical method used by economists to analyze financial trends -- has been used to successfully predict novel animal behavior.

The scientists said most ravens feed on carcasses of large animals in temperate zone forests, with individuals searching for carcasses and the finds then defended by a pair of territorial adults. Unpaired younger birds usually search individually for carcasses on adult territories and recruit each other to overwhelm adult protectionism.

However, at one raven roost in Northern Wales, the researchers observed juveniles foraging in groups -- a level of coordination not been seen before in a raven population.

The game theory analysis showed gang foraging should occur when searching for food individually is no more efficient than foraging in groups. The study also identified the availability of food as a key factor.

Our study shows the potential for game theory to help biologists understand how different social structures and behaviors evolve in different environments and in response to human activities, said Dall.

The study that included researchers from the Norwegian University of Science and Technology appears in the online journal PLoS One.