Disney's new documentary, Crimson Wing:the Mystery of the Flamingos, is due for release at the end of september. In this episode of Nature's Voice we talk to Matt Aeberhard who spent two years at Tanzania's Lake Natron to film the story of these remarkable birds. We look at why they are under threat at this their only breeding ground in east Africa. Plus we've details of how to claim free tickets to special showings of the film at cinemas around the UK.