The Weissenau Castle ruins are the remains of a medieval structure built by the Barons of Eschenbach around 1150.
The reserve is part of an Important Bird Area (IBA) recognized for its significance to migratory waterbirds.
The landscape is defined by alluvial forest zones that are periodically flooded by the Aare river, creating a dynamic ecosystem.
The area functions as a biological corridor connecting the northern shores of Lake Thun to the surrounding mountain foothills.
The Naturschutzgebiet Weissenau is a protected wetland habitat situated on the western shore of Lake Thun near Interlaken. It serves as a vital nesting and resting area for diverse bird species, including rare marshland birds, within the Aare river delta. The area features the 12th-century ruins of Weissenau Castle, a former fortification that once controlled transit through the region. Visitors can explore the landscape via a network of gravel paths that weave through reeds, forests, and alluvial meadows. The reserve is managed to balance environmental conservation with public access, requiring visitors to stay strictly on marked trails to protect sensitive flora. The confluence of the Aare River and Lake Thun creates a unique microclimate supporting high biodiversity.
The wooden footbridge overlooking the marshlands provides a clear view of the reed beds with the castle ruins in the background.
Bring high-quality binoculars as the birdlife is best observed from a distance to avoid disturbance.
Wear waterproof footwear, as the trails can become muddy after periods of high water or rain.
Check the local weather forecast specifically for the Aare valley, as winds off the lake can drop temperatures quickly.
Do not attempt to climb or enter the fenced-off sections of the castle ruins, as they are structurally unstable and protected historical sites.
Access is discouraged during extreme high-water events when paths may be submerged or closed for safety.
Strictly remain on designated paths; dogs must be kept on a short leash at all times to prevent disturbance to ground-nesting birds.
