An 18,500-acre estate in the Scottish Highlands is at the centre of Durrell's latest project, spanning over the next 100 years.

Dalnacardoch Estate, a former hunting estate in the Cairngorms National Park, is the site of the new project.

The vast land has an unbalanced ecosystem, with too many deer and too few wildcats and capercaillies.

Professor Carl Jones MBE, Durrell’s Chief Scientist, says the main focus is to rebuild lost habitats.

"Gerry Durrell realised very early on that there were no quick fixes. If we wanted to restore species and ecosystems we would have to work at it for decades.

"A few years ago, we realised, to really achieve results, we should be developing a vision that looks way into the future, and we wanted to test some of these ideas, so we looked towards getting some land in Britain for a long restoration programme."

Past human activity, spanning over three to four centuries, saw the culling of forests and habitats, meaning more species facing extinction.

The European wolf was also eradicated in the British Isles, which used to keep the population of deer down due to being their natural predators, causing a shift in balance.

Wild hunting estates in Scotland also encourage breeding the animals to maintain a high population for sport.

"To restore that you need mature, or certainly old stand forest, so it's going to take many decades to actually get the forest back into good shape where we can have a good population of species like Capercaillie.

"In recent years, we've also been interested in other species like the European wildcat."

The conversation trust has no plans to bring big predators, like the European wolf, back into the British Isles.

The professor says we do not know what will happen in the next hundred years, but Durrell has realised that breeding endangered species in captivity in Jersey and releasing them overseas is challenging, with border and travel issues.

The charity shifted to breeding animals in their home countries and releasing them as a new form of conservation.

This led to the realisation that when they do this, they improve the environment to support the success of the species, leading to the idea of rewilding programmes.