Based on avian anatomy, the PigeonBot is a research project from a Stanford University team that uses feathers for flight. Built around a wrist- and finger-like structure, the 'bot moves 40 pigeon wings via a series of springs and rubber bands. The design was validated through wind tunnel testing. Interestingly, the design doesn't incorporate flapping, instead focusing on more subtle gliding motions. Still in development, the team envisions the design being used for surveillance, recon missions, and perhaps even package deliveries.