We've seen plenty of tiny UAVs (or NAVs -- Nano Aerial Vehicles -- as they're also known), but none quite like the robo-hummingbird that's been in development at DARPA-contractor AeroVironment for the past couple of years. While we haven't heard much about it during that time, the company recently completed its most advanced prototype to date, dubbed Mercury, and it's taken advantage of the opportunity to show off all the progress it has made. As you can see in the video after the break, the bot is able to fly about and hover in place by mimicking the wing movement of a real hummingbird and, of course, be controlled completely untethered. What's more, the firm says that the final version will actually look like a real hummingbird as well, and be able to be controlled from up to a kilometer away -- even inside buildings, where a hummingbird won't look at all out of place.

[Via Danger Room]