Cors Dyfi is a Montgomeryshire Wildlife Trust reserve on the Dyfi estuary south of Machynlleth, one of the best wildlife-watching spots in mid-Wales. The reserve protects a large area of raised bog, fen, and open water — an increasingly rare habitat in Wales — and is most famous as a site for nesting ospreys.
The reserve has a visitor centre and an elevated viewing platform over the bog, from which you can see the osprey nest (when in use) and watch a wide range of wetland birds: marsh harrier, peregrine, red kite, kingfisher, and numerous wildfowl. The best time to visit for ospreys is between April and September, when the birds are present. The bog itself is an interesting habitat in any season, with bog cotton, sundew, and cross-leaved heath among the plants visible from the boardwalk. It is about 5 km from the centre of Machynlleth.