Well there´s a good Caspian underwing pattern, long grey tounges and a black rather halfmoon like band with two large white dots at the upper end.
S. Sweden 2006.12.04 (Aron Andersson)
http://www.artportalen.se/artportalen/gallery/images/swe/birds/2006/large/25068.jpg
http://www.artportalen.se/artportalen/gallery/images/swe/birds/2006/large/25070.jpg
http://www.pbase.com/slisch/large_gulls
JanJ