THE rugged and stunning wilderness of Mid Wales will be unveiled tonight as naturalist Iolo Williams explores the Cambrian Mountains.

In a new series, which airs on BBC One Wales tonight at 7.30pm, Iolo aims to explore the Last Wilderness of Wales.

The Cambrian Mountains are home to some of the rarest birds including the goshawk, golden plover and curlew, as well as the country’s only golden eagle.

But it’s the celebrated osprey that Iolo visits in this first programme, near Llyn Clywedog.

A species that has only recently returned from extinction to Wales, there have been regular sightings of ospreys fishing on the lake. Iolo meets some of the locals in a bid to capture the impressive spectacle.

Iolo then heads to the Upper Rheidol Valley in search of an animal that’s a relative of the otter and stoat, the pine marten. 

Pine marten were re-introduced to the area from Scotland after years of being presumed extinct. But Iolo’s plan to see a pine marten is initially foiled by some unexpected guests.

Iolo said: “These remote uplands form the heart and spine of Wales.

"With a handful of roads crossing this stunning area of mid Wales, much of the landscape is only accessible on foot.

"Wildlife can be incredibly difficult to find here, but when you do find it, it’s usually very special. It’s a trek in what can be truly descibed as the last wilderness of Wales.”

Iolo has walked the highlands of the Cambrians every spring for 30 years in search of golden plovers. In that time, the number of breeding pairs of golden plover have declined in Britain by over 90%. 

It’s a shocking statistic and the Cambrians are one of their last strongholds.

Iolo also visits the Marteg valley near Rhayader in search of a bird that has one of the most recognisable calls in nature: the cuckoo. But as an experienced wildlife tracker, Iolo knows that hearing one and seeing one are two very different things. 

 The Cambrian mountains have areas of conifer plantations which are home to one of our most endangered animals, the red squirrel. Across most of Wales, red squirrels have declined and disappeared as the grey squirrel population has expanded. Studies have shown that the red squirrels here in the Cambrians are genetically unique from those found in other parts of the UK, so they’re incredibly special. Iolo hunkers down in the hope of catching a glimpse of this cheeky, charming animal.