Brittany is famous for its coastal marshes. The marshes are formed in depressions, behind a coastal belt of sand or stones, or a manmade dyke. The degree of salinity of the water varies depending on infiltration of the sea and affects the vegetation and the fauna.
The marshes are favoured nesting sites for many birds. Reed warblers, bitterns, moorhens, stilts and types of duck all nest there. They are also used by migratory birds find food in the shallow salty water.
The reserve of Falguérec at Sené is particularly favourable for observing these species.
