Feathers are dead structures, providing an aeroelastic/passive flow control mechanism with more than 150 million years of evolution to optimize performance. Feathers are complex structures with a shaft providing the mechanical stability and barbs, hooked together by barbules, forming the vanes, the main aerodynamic surface of the feathers. This project concerns if feathers have evolved a micro structure that provides a passive flow control mechanism optimizing the flow over the feathers. To test how the flow is controlled we develop a 3D geometric model of a feather section that will be used to test the aerodynamic performance in a computational fluid dynamics (CFD) model. We will perform numerical experiments to explore the parameter space of the micro structures. By exploring the parameter space of feather shape (e.g. changing amplitude of the surface undulation and the angle of the barbs relative to the shaft) the performance landscape will be determined at a range of relevant Reynolds numbers and angles of attack. The result will allow us to test how feather morphology affects the aerodynamic performance. The results will be used as input to future large scale models of complete feathers and act as inspiration for passive flow control in technical applications.