The inverted delta of the Świna river
The inverted delta of the Świna river covers an area of over 3000 ha of dumpy and marshy islands, fens and tidal waters, forming part of Szczecińskie Lake. This picturesque archipelago of wet and boggy islands, cut by innumerable straits and canals, is nationally unique. Home to man for millennia, the original names of various islands, such as Zajęcze Łęgi, Wydrza Kępa, Koński Smug, Warne Kępy, Trzcinice, Gęsia Kępa, Wielki Krzek and Karsiborska Kępa, have vast historical origins.
The Świna delta is one of the major natural bird habitats in Poland, recognised by Bird-Life International as an Important Bird Area (IBA). It is inhabited by an estimated number of 240 species of birds, including 160 hatching species. It also forms a nesting site for nearly 1% of the entire population of sea eagles in Poland.
The complex of wet and boggy pools of the Świna delta, forming part of Szczecińskie Lake, is an extremely precious overwintering and moulting site for various bird species, and is of pan-European importance. During the passage period, i.e. in Spring and Autumn, you may spot flocks of several thousand water birds, migrating along the Oder river basin and the Baltic seaside. The Aquatic Warbler, a small passerine bird, the global population of which comprises no more than 20 000 males, is the real gem of the Świna delta. Once proliferating in turf fields and in dumpy meadows, the species has now become rare, due to the disappearance of suitable nesting site habitat. In the Świna delta, which is the farthest western home to the Aquatic Warbler’s population, this species has found a home in one of the major biotopes in Poland.
In consideration of its exceptional natural values, the Świna delta, together with the entire area of the Oder estuary, was recognised by the International Friends of Nature Association (Naturfreunde Internationale-NFI) as “Landscape of the Year 1993-94”. Since 1996, due to its biodiversity and unique landscape features, the Świna delta, with an area of approximately seventeen hundred hectares (1700 ha), has formed part of the Wolin National Part.
For many years, the island areas were used for agricultural purposes, mainly as grazing land. This fostered the development of valuable plant clusters. The extensive grazing practices performed in the accessible sections of the islands contributed to the survival of precious meadow formations (such as brackish, bulrushes and dumpy meadows). After agricultural activity ended (in the 1980’s and 1990’s), these meadows, including salt grasslands, were “invaded” by the predominant plant complexes, including especially the Phragmitetum australis cluster. Its name comes from the most prevalent plant species, namely the Common reed (Phragmites australis) which grows up to 3 metres.