The Rhine delta of Lake Constance is the river delta on the southeastern shore of Lake Constance, which the Rhine (also called Alpine Rhine (Alpenrhein)) has formed in a former sea area. It lies mostly in the Austrian province of Vorarlberg, smaller areas are in the Swiss canton of St. Gallen. The two peninsulas in the lake are called Rheinspitz (west) and Rohrspitz (east). Geography The delta of the Alpine Rhine forms a common delta area with the eastern deltas of the rivers Dornbirner Ach and Bregenzer Ach. In the north, the border of the Rhine delta runs along the shore of Lake Constance. The southern border depends on the course of Lake Constance after the melting of the Rhine glacier. It is usually at least a few kilometers long. The area covers an area of 2,065 hectares, of which 1,960 hectares are on Austrian territory. About two thirds of the Rhine delta consists of water (1,300 hectares), which generally has a depth of just a few meters. Nature park The Rhine delta is the largest wetland biotope reserve on Lake Constance and extends from the mouth of the Alter Rhein over the mouth of the Neuer Rhein to the Dornbirner Ach in Hard (Vorarlberg). Both Austria and Switzerland have each designated the area as a nature reserve. Due to its great ecological importance, the Vorarlberg area of the Rhine delta is a wetland of international importance (a so-called Ramsar site). Since 1995, the nature reserve is part of the Natura 2000 network focussing on fauna-flora habitat and bird protection. Fauna and flora Fauna The variety of birds inhabiting the nature park contributes significantly to this ecological importance. To date, well over 300 bird species have been observed which makes the Rhine delta nature park popular among ornithologists and bird watchers. Shallow water and silt areas are important resting and breeding places as well as food spots for water birds and waders. Numerous rare and endangered species breed in the about 2,000 hectares of wet meadows, reed beds and riparian forests. The Rhine delta is an ideal habitat for many amphibians, too. So far, nine species and a hybrid form (the edible frog) have been identified in this area. The large populations of water frogs are remarkable. European tree frogs and crested newts are also found locally in considerable numbers. Moreover, five native reptile species live in the area. In