The bird with the white ring 22C7 seen on the Tanybwlch side of Aberystwyth harbour by Cris Bird on 5th and photographed by Laurie Wright on 4th had come from Hosehill Lake in West Berkshire where the Reading and Basingstoke Ringing Group group ring the young from a breeding colony there. 22C7 was ringed as a youngster on 7th June 2010 and was last seen there on 5th July. The next and only other sighting so far was at Aberystwyth.
As well as these details I was also sent the Group's 2010 Ringing Report which included a facinating section on the dispersal of young Black-headed Gulls from that site. See www.rbringing.co.uk