Marazion Marsh RSPB Reserve

Marazion Marsh is a Royal Society for the Protection of Birds reserve in a shallow river valley west of Marazion in Cornwall. It sits half a kilometre from the coast behind a shingle bar and small sand dunes, and holds Cornwall’s largest reed bed. The marsh lies in an embayed estuary between Marazion and Penzance, separated from Mount’s Bay by a fossilised sand and gravel barrier. A discontinuous sand dune system crosses the main road between the two towns, and the Red River drains the Phragmites-dominated wetland. Lower Devonian slates form the solid rock beneath recent deposits of unconsolidated sediment up to ten metres thick. The site is recognised for its biological importance and has been designated a Site of Special Scientific Interest since 1951. It supports rare plants such as pillwort and provides feeding grounds for passage waders and wintering birds. Up to five bitterns overwinter here, though the reed bed is below the twenty-hectare minimum size needed for breeding. In 1990 the St Aubyn Estates agreed a lease with the RSPB to restore the drying reed bed, and emergency flooding created a large pool within three days. The reserve was later declared a Special Protection Area in 2001 for aquatic warbler and bittern. Visitors walk along paths through reed beds, open water, unimproved grassland and woodland. The reserve also contains willow scrub managed to favour bitterns and other wildlife. Dragonfly counts after restoration reached 154 individuals of eleven species in a few weeks. The marsh’s layered sediments reveal past changes in salinity and vegetation, studied through boreholes and pollen analysis. A pot of corroded Roman coins found in a drain shows earlier human activity on the site.