Vienna's Danube Island, a river island artificially created some 20 years ago, has become a recreational retreat for tens of thousands of city dwellers. To tourists, it is an attraction praised in every traveller's guide. Sun worshipers, cyclists, skaters and night owls invade the island from the first days of spring until the fading of the autumn sun. No-one associates the island with wildlife and wilderness, and yet, unnoticed by most visitors, a secret army of wild animals has invaded the banks, forest and bushland right in the middle of a big river and a large city. Stone martens, beavers, rabbits, deer, herons, cormorants and black kites, various fishes, toads, frogs and insects have conquered the island and turned it into their own hunting and breeding grounds.