Caspian Gull

2nd winter Caspian Gull, Milton, 5th Dec 2006, © Dick Newell
This is the third Polish-ringed Caspian Gull this month. The ring-number of this one is 6P15. This is a particularly stunning individual, probably a male. However, the bill looks slightly off and given its origin in a mixed colony, maybe it is not pure. (RGN)
Postscript: This bird was ringed in a colony of mostly argentatus Herring Gulls on the Vistula River, Wloclawek on 13th May 2005. Parentage unknown, but probably cachinnans x argentatus.