Series 2
4 episodes · 2026
Iolo Williams explores four of Wales's longest river valleys from sea to source.
1Usk
Iolo Williams explores the Usk valley, from Newport’s urban wildlife to ground-nesting birds, a huge lesser horseshoe bat roost and scarce firecrests.
2Tywi
Iolo Williams explores the Tywi river valley, from Llansteffan’s coastal dunes to fallow deer ruts, ancient oak woodlands, and the remote heights of the Tywi Forest.
3Teifi
Iolo explores the Teifi river valley, and finds a slow worm hunting, meets a coracle fisherman, is thrilled by a fishing Otter, and watches a pair of kestrels at their nest.
4Deefinale
Iolo explores the stunning Dee valley, from wintering birds along the estuary, to displaying black grouse on moorland, rare freshwater-pearl mussels, and spawning sea trout.
