Well, at least a few are.
Around the end of January, through February into the beginning of March, I saw quite a few of these Black Headed Gulls, with the large coloured rings on. Today I have seen at least four different ones, that have returned to the area.
I found online, the group that was doing this and reported all my sightings.
In late Spring I received an interesting email from them. One of the birds I saw several times, 225B, was seen here on the 8th March, the next sighting was ten days later, 1,100 miles away in Lithuania !!
Mr 225B was back here today, but this is Mr 245B.
How great your photography is aiding in tracking this species. Keep up the good work. So interesting, too, that they travel so far, or where do live for context?