Wow every days a school day!I remember a similar problem with cats and scared them off with exploding pellets from my .22 Crossman. I used to carefully powder Swan Vesta match heads and pack it in to the pellets with a bit of tissue and blob of glue to keep it all in place. Wait till cat was walking past something hard and shoot. Nice crack as the pellet struck hard surface making cat leg it. Fed up with grinding down match heads I then put fins on the matches and seated them on a wad of tissue to fire them. This was better as there was a flash as well!