This set: photos from the Woodland Park Zoo in Seattle. It's a small zoo, and I have mixed feelings about its enclosures. But at the same time, zoos help preserve species and inform the public, and you can tell they're doing the best they can.
I am surprised, actually, that it took the squirrels this long. Granted, this could be merely the first time I've caught them, but judging from the amount of seed I usually have to replenish, it couldn't have been happening long.