CDS Lecture Series: Andrea Cavagna, "Inter-Individual Interaction in Collective Animal Behavior"
Wednesday, April 8, 2009
2460 A.V. Williams Building
301 405 6576
Control and Dynamical Systems Invited Lecture Series
Inferring the Inter-Individual Interaction Using Empirical Data in Collective Animal Behavior: The Case of Starlings
Centre for Statistical Mechanics and Complexity
Bird flocking is a striking example of collective animal behavior. A vivid illustration of such phenomenon is provided by the aerial display of vast flocks of starlings gathering at dusk over the roost and swirling with extraordinary spatial coherence.
Both the evolutionary justification and the mechanistic laws of flocking are poorly understood, arguably because of the lack of empirical data on large flocks. Even though numerical models of collective animal behaviour are countless, in absence of large-scale reliable data in three dimensions it is hard to assess the validity of the models' assumptions and results.
We report here a quantitative field study of flocking. By means of stereoscopic photography, computer vision and statistical mechanics we measured for the first time individual three-dimensional positions in compact flocks of up to several thousands birds in flight. Thanks to these data we were able to study the way birds interact with each other and to measure how the interaction decays with the inter-individual distance. Our results suggest that the nature of the interaction ruling collective animal behaviour is quite different from what was commonly assumed by most models and theories.
Andrea Cavagna is a researcher at the Centre for Statistical Mechanics and Complexity at the Italian National Institute for Condensed Matter Physics in Rome and teaches at the University of Rome. He received the Ph.D. in theoretical physics from the University of Rome and did post-doctoral work at both Oxford University and the University of Manchester.
A theoretical physicist by training, his research focus has been in the statistical mechanics of disordered systems. More recently, he has begun to explore questions of collective animal behavior by applying methods from statistical physics to solve biological and ethological problems. For the last three years, he has been a coordinator with the E.C.-funded STARFLAG Project to collect three-dimensional data of free-flying starlings in large flocks and to understand the fundamental rules of interaction among birds.