I watched the third episode last night. Three things that impressed me:
1. The small reserve at the beginning, Llangloffan Fen, reminded me a lot of a reserve near me run by the Scottish Wildlife Trust called Cathkin Marsh. Like the Welsh reserve, this is a marsh with some open water, surrounded by farmland (and in the Scottish reserve - landfill). It's one of those places hardly anyway knows about but it's a little oasis of wildlife, as Iolo said about Llangloffan Fen.
2. The sighting of House Martins nesting on a sea cliff on the coast. I've never seen these birds using natural habitat before, it was quite a surprise.
3. Demoiselle damselflies (I'm not sure exactly which species) over a river. Beautiful in flight.
Looking forward to seeing what's in the last episode.