From Slovenia to south-west County Kerry, Barra Best uncovers how passionate people across the UK and Europe are helping bring endangered species and environments back from the brink of extinction.In the German town of Burghausen, Barra meets one of the volunteers who has gone to extraordinary lengths to ensure a quirky looking bird continues to exist. Previously extinct in the wild, a breeding programme saw northern bald ibis chicks born in captivity. But when it came to showing the migratory birds where to spend their winter, it was up to volunteers to show them the way – meaning a spectacular journey over the Alps.Off the coast of Ireland's County Kerry, the Atlantic Ocean is home to an abundance of nature, including dolphins, whales and seabirds such as puffins and gannets. Could the presence of super-sized oysters found there play a part in saving our oceans' diversity?Hitch a ride with Europe's largest land mammal as a group of bison are relocated from Sweden to the wilds of Romania, while in the Scottish highlands discover how a simple change in mountain bikers' behaviour is helping the creature called 'the horse of the forest' in Scots Gaelic – the capercaillie.