The US military's UAV fleet will soon be getting a small addition — DARPA's hummingbird-shaped covert surveillance drone.

Dubbed the Nano Hummingbird, this Nano Air Vehicle (NAV) is built by AeroVironment. It's designed for urban surveillance missions and has just passed DARPA's Phase II technical milestones.

It mimics more than just a hummingbird's looks, mind you. By copying the bird's aerodynamics and wing movements, the NAV is able to hover for eight minutes while easily moving in and out of buildings. The tiny, 10-gram flier is also able to operate in windy conditions — withstanding up to 5MPH gusts. The drone is controlled via a video stream from its deployment aircraft.

So the next time you see a hummingbird with four prongs instead of tail feathers, be sure to smile for the camera. [UnCrate via Ubergizmo]