Apparently this is the same bird as the one found in February 2009 by Jørgen Munk Petersen, at the same lokation.
Details how to ID this type, will follow soon.
Photo: Troels Eske Ortvad, March 2011, Christianshavn.
Photo: Rasmus Strack, February 2005, Kattinge vig.
Adult male, the same bird as above from Christianshavn.