Vresen is a small islet with a little vegetation, surrounded by shallow sea areas.
This is an important site for wintering Somateria mollissima; although numbers fell in the early 1990s due to siltation of mussel banks caused by the construction of the Great Belt Bridge, numbers in the Great Belt area as a whole seem to have recovered.
National Low International High3,470 ha of IBA covered by Special Protection Area (Vresen and surrounding sea areas, 3,470 ha).
BirdLife International (2022) Important Bird Areas factsheet: Vresen and sea area between Fyn and Langeland. Downloaded from
http://www.birdlife.org on 15/08/2022.