"The Nérac Ponds are located in the towns of Altenach and St. Ulrich in the Sundgau area. Dating back to the 17th century, this set of five ponds, about twenty hectares all told, is a transitional environment between beech forest and cultivated fields. Used until the 1970s they were then transferred to the General Council of the Upper Rhine in the early 1990s. Their size and lack of maintenance over a period of many years allowed them to develop more naturally, despite their typical Sundgau-fishing-pond morphology. Thus their steep banks only allowed the installation of a light riparian vegetation curtain. Only the fourth pond had a large reed bed. Furthermore, constant water levels and low diversity of habitat were not conducive to the use of the ponds by a variety of wildlife.
However, ornithological studies of this site have shown that more than a hundred species of birds frequent Nérac ponds, either to nest there or for staging. Rare species such as Penduline Tit, Osprey, Hen Harrier and Common Crane have been observed there. In addition, their location between forest edge and open field provides considerable potential for hosting biodiversity.
A topoguide available from the Sundgau Nature House situated in Altenach, or from the Tourist Information Centre, offers a two to two and a half hour walk to discover this site so conducive to the observation of birds.