Mute swans ("Cygnus olor"), Black-headed gulls ("Chroicocephalus ridibundus", Syn. "Larus ridibundus"), Mallards ("Anas platyrhynchos") and Feral pigeons ("Columba livia"), view across Danube towards Donauinsel, Brigittenauer Brücke and Donau City with DC Tower 1 (height: 220 m) in low Stratus clouds; Vienna, Austria.