We're under assault by 2 red squirrels. Generally, I let them get away with a lot, but when they're crawling up, down, and over the house (pooing and peeing along the way), it's game on. Threw my 4x scope on yesterday, spent a couple dozen shots sighting in and getting used to it again, and missed the shot on a perfect set up due to slightly longer range than I'm comfortable with (30yds)... and I twitched. I'm not a very experienced hunter, shoot a lot more paper than fur or feathers. Got another chance today at about 25yds (very good distance for me), decided I was comfortable going for a headshot (my first on a squirrel), steadied much better than the day before, and the poor bastard dropped like a brick.
There's at least one more out there. We'll see...