Bird flocks and fish schools behave like soft crystals ^{CEFR B1}

Researchers at New York University developed a mathematical model that explains how flocks of birds and schools of fish move together. Earlier work had outlined general rules for collective motion, but the detailed mechanics were still unclear. The new paper appears in Physical Review Fluids and builds on findings from NYU’s Applied Mathematics Laboratory.

The model treats animals as if they were atoms in a soft crystal, arranged in a regular lattice and connected by flexible, spring-like bonds. In this view, groups keep roughly even spacing and behave like an elastic material that can be easily deformed yet remains responsive to air or water flow and to nearby objects or predators.

To test the model, the team examined past experiments, including tests with mechanized flappers driven by motors and fitted with 3D-printed wings. The mock flock moved through water at different speeds and could arrange itself in a line; its behaviour matched the model’s predictions. The authors note potential applications in aerospace and automotive engineering, robotics and energy harvesting. The work was supported by a grant from the National Science Foundation and included undergraduate researcher Jiajie Wu.