My roommate showed me on awesome video over on ted.com This guy is making a vending machine for crows. crowboxunleashed.com is the site to read up on it.
I think it's an awesome idea. If we had more than grackle's here, I would want to build one. But I don't think grackle's are quite clever enough for it.
What I loved most about watching his video is Betty the New Caledonian crow. I already knew New Caledonian's were tool users, but I was blown away when Betty made a hook out of a bit of wire to get a treat out of a container. It was freakily awesome.
But I'm a zoo nerd like that.