Nietoperek Reserve – the biggest bat wintering site in Poland

The undergrounds of Międzyrzecze Fortified Region are the biggest and the most important bat wintering site in Poland. Every year, between 20,000 and 30,000 individuals belonging to 12 species winter there. This is the biggest winter colony of these mammals in Central Europe. In August 1980, on the basis of a decree issued by the Minister of Forestry and Wood Industry, the "Nietoperek" reserve was created in a part of the underground area of 2.5 ha. In December 1998, the "Nietoperek II" reserve was established, thus encompassing the protection of the entire Międzyrzecze Fortified Region.