Kopacki Rit (pronounced ko-pachkee rit) Nature Park is a flood area ( rit means marsh) between the Drava and Danube rivers in the Osijek-Baranjska region of eastern Croatia. Sometimes called "the pearl of the Drava", the nature park covers 177 sq kilometres holding more than 20000 waterbirds in winter of 267 different species. You'll find cormorants, herons, gulls, terns, ducks and egrets Some of the birds such as the black stork and the great white egret are rare in Europe but the most prized inhabitant of Kopacki rit is the largest Croatian eagle, the white-tailed eagle.
As the largest remaining wetlands in Europe, Kopacki rit changes in accordance with the seasons. In spring, high waters, mostly from the Danube, flow in the marshlands bringing fish that come to spawn in the shallows The warmth makes the water plants, plankton and insects flourish making it one of the most fertile spawning areas of the Danube region Spring is also marked by an explosion of frogs.
In the central part of the reserve is a lake that is connected to the Danube by a canal that serves as a conduit for most of the water throughout the marshlands The north part of the park is composed of willow, poplar, oar and ash forests. Here you'll find deer, wild boar, fox wildcats, martens, weasels and other creatures. https://www.croatiatraveller.com/National%20Parks/Kopacki.htm