Iolo Williams is exploring the wildlife of the old coalfields of south Wales. He heads up the valleys north of Newport, starting off at Blaenavon, where he locates an elusive bird that very few people ever see — a long-eared owl. It really is a stunning bird, and Iolo has a rare chance to help ring the owl's chicks. Peregrine falcons are known to be the fastest birds in the world — able to reach speeds of over 200 mph when hunting. Iolo enjoys watching a successful breeding pair nesting at a site in Ebbw Vale. Nearby, ground that used to be the site of an ironworks is now an important wildlife haven full of wild flowers and butterflies. The star attraction is the marble white, a butterfly that's only recently spread into Wales. Iolo also visits the "silent valley" and finds lapwings nesting on an old coal tip above New Tredegar.