Hi Stew, I haven't come to a conclusion yet but I have not had a great deal of success with the GoodNature A18 trap. In the same time as it killed 3 grey squirrel I shot 26 with my air rifle from a hide. On top of that GoodNature now say not to use their traps if there is any chance of red squirrel, dormice, or pine marten. But, as far as I can see, it will kill any wildlife that can get its head into a 45mm hole so, for the moment, I've stopped using it. I'll set it up again but with a camera trap to monitor any by-catch and I'll abandon it if there is.