Support the extension
A. Lasthukin ( www.xeno-canto.org )
The Caspian Gull is increasingly seen in the Netherlands. The difference with the Herring Gull is difficult to see. The Caspian Gull seems more erect in posture.
http://en.wikipedia.org/wiki/Larus_cachinnans
http://eol.org/pages/1178521/maps