I've always used en empty washing up liquid bottle to give them a surprise squit up thier behinds - as Jonesy said in Dad's Army - they don't like it up 'em Mr Mainwaring! And by golly they don't! I've always thought this to be a kinder way to repel these unwanted visitors. I have 3 of my own - but we do have one or 2 really nasty cats around who pick a fight with a twig if given half a chance. One particular black cat is now known as Satan and is extremely belligerent!

Now back to the problem....obviously you can't be there all the time with bottle or water pistol at the ready. I came across this handy device from a firm I recieve a newsletter from and will be buying a food dehydrator very soon. This looks just what the absentee gardener needs to repel unwanted visitors. A water supply is required.

Heron Scarer from Westfalia at our Safety and protective equipment inside the Tools shop

Some discretion may be needed when turning on - for instance you wouldn't want to soak the postie or yourself when approaching the house - but I'm not sure of its range and you could work out a suitable spot from which to radiate the line of fire! Could also deter pesky neighbourhood kids if you're blighted by them too?