Pining for Marten?

George Monbiot has joined the enthusiasts for culling the alien Grey squirrel in the UK by encouraging the return of the Pine marten (Martes martes) throughout the land (http://www.theguardian.com/environment/2015/jan/30/how-to-eradicate-grey-squirrels-without-firing-a-shot-pine-martens). The described Irish experience certainly sounds more effective than the other expensive methods of culling (by shooting, trapping and poisoning etc). It would also be nice to (occasionally) see more of the Pine marten. Having said that, there is no certainty that once this little predator had munched its way through the greys (who are linked to the decimation of the native Red squirrel and cause real damage to pine forests), they would not start to eat species of mammals and birds we would like to conserve. This is a standard problem of advocated biocontrol methods (they need to be measured over the long term).