Barra's Return of the Wild

From the rivers of Northern Ireland to the slopes of Spain, Barra Best discovers how passionate individuals across the Europe and the UK are helping species and environments under threat.

By the banks of the Ballinderry river, Barra hears how farmers and conservationists are working together to turn the fortunes of a miraculous mollusc around. Freshwater pearl mussels can filter up to fifty litres of water a day, but pearl fishing and pollution means the creature's future is in peril. As he helps release mussels into the river, Barra discovers how coordinated efforts mean the mussel's future in Northern Ireland is looking brighter.

In Scotland, cameras follow work as a pre-release enclosure is prepared for wildcat kittens in an effort to ensure Scotland's rarest and most threatened mammal continues to populate the Cairngorms. A farmer in the Netherlands explains how he's ensuring the country's national bird can thrive on his land once more, while in Ireland, discover how a change to the country's motorways has helped save another farmers' friend.

On a dusty hillside outside Grenada in Spain, Barra hears how an ancient irrigation system developed over 1,200 years ago could now offer a partial solution to the Costa del Sol's water supply issues.

In Northern Ireland, Barra meets the team investigating the promising possibility that a slippery substance found in plentiful supply around the country's coast could help reduce the methane output of cows – a major agricultural source of greenhouse gases.

The moose's turn as an unlikely Swedish reality TV star is helping shine a light on the species' plight. A deep dive below the surface of a German lake reveals the spectacular natural miracle being aided by a group of volunteers.

By Rome's historic Villa Borghese, Barra hears how a creature synonymous with the eternal city is now making a return to its parks and streets.In Spain, a farmer reveals how she's learning to love the infamous vulture, which benefits the area by helping sanitise forests and hillsides.

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.