posted 11 years ago
It's also very seasonal and it changes year by year. Here (west Wales, so not dissimilar to where you are I think), we have seen a few, limited damage, our immediate neighbour is plagued by them and has lost pretty much the whole garden, the farmer up the road is on a mission to get rid of them too, while half a mile up in the village, no one sees any.
As Michael Cox said, the current population will be in balance for the situation as it is at the moment (predation, food, etc).
It really sounds to me like you need to learn a *lot* more about local conditions - and over a time back in history and a while of observing yourself, a few seasons at least - before you have enough info to start trying to manipulate a wild population.