Squirrel hunting is a fun sport and an excellent one to introduce novice hunters to sportsmanship and gun safety. About a year ago I picked up Crosman Phantom .177 cal. airgun for squirrels and have really enjoyed the much improved sport of airguns. This gun is a "springer" but the PCP airguns are lethal and legal, in many states, for larger game such as hogs and whitetail deer. I was quite surprised, a few years back, to learn that Lewis & Clark carried an airgun on their expedition to the Pacific Ocean. They had it designed to shoot, I believe in .54 cal., the same size minnie balls that their black powder guns shot to make it easier only having to cast one size ammo. Couldn't believe none of my teachers had ever taught us anything about such a revolutionary weapon for the times. As far as migration, I have read or heard of Red Squirrels moving in hordes before.