Pictures of the bird first:
Originally I had thought it was an adult based on the all white flight-feathers. And that usually results in the correct aging of the bird and no need to take a closer look.
But thanks to the leg band I found out that the bird was banded last December as a 1st year bird in the same area. Thus making it a second year bird now and not an adult.
I was understandably confused and while researching it I came across a forum where someone had presented the exact same problem of the exact same bird! In fact he was confused from my photos because he had seen the same bird last year as a 1st year bird at the same location.
After a closer read of my field guide (unfortunately I left my gull book at home in Canada so I don't have much else to read) I noted that the "2nd year bird looks like the adult but has variable black markings on wing tip". I would interpret that as: there are black markings on the wing but they aren't consistently patterned. But it seems that occasionally the black markings sometimes do not even exist!
Maybe this bird is a bit mature for its age?! :p
There is one hint for aging the bird though. And that is the bill colour. Check out the dull red on the base of the bill. Thanks Morten for pointing that out.
Now compare that bill to this bird I photographed in October of this year in Spain:
And a closer look at the bill - it is scarlet red instead of dull red at the base, thus confirming that it in fact is an adult and not a 'premature' 2nd year bird:
If it weren't for the leg band and the fact that the bird is over-wintering in the same location as last year then I suspect that most people would have incorrectly aged this gull! Gulls are notoriously variable but I think that most people would have confidently aged this Med Gull as an adult. It just goes to show that one can never be 100% confident when it comes to bird identification and especially gulls, and it's always worthwhile to be critical of ones own identification.
Never a dull day! ... unless you need to study for exams...
