Posted: 25/06/2013 at 17:06
I'm pretty sure you can legally just put a 4.5mm hole through a grey squirrel, as long as you've got the landowner's permission and you're really careful not to send pellets beyond the boundary ("squirrel fell off other side of fence with pellet embedded" is probably okay) or to startle anyone by shooting from within 50 feet of the centre-line of a public highway.
Yes, really, within 50 feet of the centre line, whether it's a single-track farm lane 9 feet wide or the A1 at Peterborough (where you'd be on the hard shoulder).
I suspect the fairground airguns were ordinary airguns with an adaptor to hold the corks. As long as you're over 18 and it doesn't shoot over 12 foot-pounds of energy, you're okay owning such a weapon in most places and can lend it to anyone over 14, if I'm remembering correctly. Be aware that a 0.5g .177 pellet with 11.9 ftlb of energy in it is a lethal projectile, and hazardous after a ricochet, so be careful with it.
Rather more effective than the corks would be a paintball marker, but you may get complaints from owners, who feel their precious little sociopaths should be allowed to torture your songbirds to death without fear of getting a sticky mess in their fur and a bruise.
Did you hear about the scientist who crossed a Scotsman with a Quaking Aspen and got something that can hold onto a grudge for 30,000 years and its wallet for more than twice that long?