The Murmurator is a semi-improvised immersive composition created using a novel, biological model-driven digital musical instrument. The system is built around a three-dimensional bird flocking simulation that spatializes and affects different sonic characteristics of a corpus of granularized audio files. Diffused over a multi-channel system, the work alternates between densely immersive ambient textures and isolated spatialized gestures and back. The result is a work that harnesses the emergent behaviors of the biological model while at the same time maximizing “liveness” and the improvisational decisions of the performers through exploration of the musical space of the performance venue.