Caspian Gulls: some obvious and some not so obvious ones

This post shows a selection of birds that were present at the landfill site at Klaipeda, Lithuania (Dumpiai dump) between 12 and 16 September this year. Photos are not in any particular order. Most photos show rather clear and readily identifiable Caspian Gulls but 3 or 4 are perplexing. I have to admit to being confused by these perplexing ones - although many show plumage features not normally associated with cachinnans, ALL of them called like and had the classic long-call posture of this species. We can discuss the identification of these tricky birds long and hard, but ultimately we cannot be sure what they are, as all are unringed and so are of unknown provenance. I hope you enjoy musing over them...

As always, opinions are welcome.

Same bird is shown below.

Same bird as above. Looks good with wings open.

Same bird as above: looks less convincing

The same bird as above.

Same bird is shown below.

Same bird as above.