In this week's programme we have a field report from South Georgia where Tony Martin, Professor in Zoology at Dundee University and working with the South Georgia Heritage Trust, has embarked on a programme to remove 100% of rats on South Georgia. Human activity over the decades and centuries have inadvertently introduced Brown Rats to islands and mainlands and the rats have driven local extinctions of birds and caused havoc on many seabird populations, eating the chicks in the nest. Is the wildlife benefit worth the effort it takes to return such areas to a situation before Brown Rats were introduced? Monty Don also speaks with environmental author Emma Marris.