HOWTO build a robotic squirrel-squirting water sentry-gun, with python

Kurt Grandis needed to fight the squirrels in his backyard bird-feeder. So he turret-mounted a Super-Soaker, rigged for computer-control, and used python to program it to detect squirrels (distinguishing them from other critters, such as birds), target them, and squirt them. In this 26 minute technical presentation from Pycon US, he explains how to teach a computer to answer the question, "What is squirrelness?" and to camp on the feeder and target them. The amazing thing is how it takes the infinite patience of a computer to outlast the persistence of a squirrel. Jump to 15:45 for about a minute and a half of pure gold squirrel warfare, complete with Wacky Sax.

Militarizing Your Backyard with Python: Computer Vision and the Squirrel Hordes (via Naked Capitalism)