Danube-Gunz interglacial age of about 900,000 to 940,000 years. There are however indications that the Uhlenberg Profile may still be placed within the Pliocene, and it would thus not correlate with the Danube-Gunz interglacial. Also uncertain is its association with the North German classification because of its position in the underlying stratum of the Gunz it could correspond to the Bavelian or the Waalian interglacial. The Danube-Gunz corresponds at least in part to the Swiss Deckenschotter glaciations. Danube-Gunz interglacial The Danube-Gunz interglacial (), Danube-Gunz warm period ("Donau-Günz-Warmzeit"), often just Danube-Gunz, or also Uhlenberg interglacial ("Uhlenberg-Warmzeit") is the second-oldest named warm period of
Birds of the Danube Delta and mixed form of colonial nesting. Such an observation and interpretation of the colonial nesting origin in the Danube Delta may constitute an argument for properly explaining the colonial nesting phenomenon in different regions or the globe. Birds of the Danube Delta Following an almost two-decade (1951–1970) research of the Danube Delta territory, 274 bird species were identified of which 176 were brooding (sedentary and migratory) and 98 non-brooding ones (winter, passage, erratic, and accidental birds). The species of brooding birds occurring in the Danube Delta were classified into 12 main biotopes, the classification criterion being represented by the nesting