Black-headed or Common Gull?

[marsmuusse]

Today I photographed this bird. NLA 3.610.992. After entering the code I checked the life history, which appeared to be somewhat funny:

History:
NLA 3.610.992 Stormmeeuw (canus) - 20-11-2012 strand Katwijk
NLA 3.610.992 Stormmeeuw (canus) - 29-01-2012 strand Katwijk
NLA 3.610.992 Kokmeeuw (ridibundus) - 03-12-2009 Buitensluis 1-2, Katwijk, Zuid-Holland, NL
NLA 3.610.992 Kokmeeuw - 03-12-2009 Buitensluis 1-2, Katwijk, Zuid-Holland, NL
NLA 3.610.992 Kokmeeuw 22-03-2003 Buitensluis 1-2, Katwijk, Zuid-Holland, NL (ringed, >2cy).

A Black-headed Gull that transformed into a Common Gull!
Ring re-used? Wrong ID?

[marsmuusse]

Just the most probable error: bird ringed as Common Gull, but notes in the book are Black-headed (like the previous bird ringed, and the next bird ringed). Could happen on a busy day ringing. But... ring read twice on the beach, and entered as Black-headed as well. Now, what are the chances this accumulation will happen???