On Sun, 10 Feb 2008 20:55:59 +0100, David in Normandy
wrote:

Whatever solution, you may need to persist - it is an
ongoing war.

Thanks for your suggestions. Yes, I should have googled first; I see
you are right about it being a regular topic here. Your reply seems to
summarise the solution options nicely, so thank you for saving me a
lot of research. Yes, the lawn is indeed right next to open fields!
Perhaps a pet owl or a predatory cat might is the answer...

JD