I've hammered the squirrels myself and have two retired fellas with shotguns shooting there too, although they prefer to shoot the pigeons. I'm overrun with rabbits but the warrens are so deep that ferreting isn't very effective - the rabbits run around underground and the ferrets get bored and come up with their claws full of fur. To make things more difficult I have warrens with foxholes in the middle - the ferreters won't send them down because they don't know which holes lead to rabbits and which to foxes.
To cap it all I'm told there are now deer there too.
All in all I'm having a torrid time with pest control at the moment and I'm supposed to be felling four acres this March.
On the bright side, the FEO has been up there and cleared it for 0.17, 0.22 and Hornet so at least I'll be able to zap the buggers from 100yds ( except the deer but I've got a man with open FAC to sort them ).