The RSPB Coed Garth Gell reserve lies in the hills immediately north of the Penmaenpool bridge on the Mawddach estuary. In spring, you can hear pied flycatchers, wood warblers and redstarts in the deciduous woods while ravens and buzzards are present throughout the year. There is an attractive 3½ mile circular walk through oak wood and scrubland, making use of some of the tramways left over from long gone mine workings. A second reserve, Arthog Bog wetlands is situated between Arthog and Fairbourne and has wheelchair access from the car park at Morfa Mawddach train station.
For further information on the RSPB reserves see their website.