Currently, I have quite unusual "pet system". I have a bird feeder made by myself that is placed right on my window from the outer side. I have my workspace next to this window and watch many different birds every day while doing something. My bird feeder attracts great tits, blue tits, sparrows, greenfinches, nuthathes and bullfinches (my favorite guys :) Couple of times I've seen even a woodpecker! I think it's great to have this many "pets" at the distance of my arm, which at the same time are free of being held in a cage.