The extraordinary synchrony of motion exhibited as a flock of birds arcs overhead, or a school of fish turns, as a ripple of light, is captivating. Like some animate fluid the individual organisms appear to move as one, their minds seemingly connected by an invisible network. Professor Couzin’s lecture will provide a visual guide to collective animal behaviour, particularly focusing on migration, using the latest imaging technologies to reveal how and why animals exhibit collective motion, the huge impact swarms have on human life, and the remarkable collective sensing and decision-making capabilities that have arisen in animal groups.