Gull flock, Poland (1 Viewer)

[JayFeatherPL]

19th October, Northern Poland, Baltic Sea
I know it may be impossible to ID every gull there because of no photos showing the pattern on the wing, but I'd like to know at least the most likely options.
Each gull individual has its unique number or letter.
29 photos: the rest of the photos are in the comments.
These are my guesses:
1 - Cachinnans?
2 - Cachinans?
3 - Argentatus?
4 - 3rd winter Cachinnans?
5 - Michahellis?
0 - Argentatus?

A - Argentatus?
B - Cachinnans?
C - Cachinnans?
D - Argentatus?
E - Cachinans?
F - Michahellis?

X - Michahellis?
Y - Cachinnans?
Z - 3rd winter Cachinnans?

Are these correct?

 

[JayFeatherPL]

The rest of the photos:

 

[lou salomon]

Most are correct. However, there is no michahellis in these pics - 5 and X both are also argentatus.
3 in 7105 is not the HG from before, maybe a cachinnans but can't tell for sure.
Nice 'thayeri-pattern' in 2 (cachinnans).

 

[JayFeatherPL]

Most are correct. However, there is no michahellis in these pics - 5 and X both are also argentatus.
3 in 7105 is not the HG from before, maybe a cachinnans but can't tell for sure.
Nice 'thayeri-pattern' in 2 (cachinnans).

Thanks a lot!
But could you explain to me why 5 and X aren't michahellis? The bright yellow legs, a prominent red eye ring and a massive bil all suggested me a Yellow-Legged Gull.

 

[lou salomon]

like 0 and 3 (argentatus, 0 also with yellow legs), birds 5, F and X also are late moulters, with a retained old p10 (and with a very large p10 mirror), unlike michahellis which at this time of year usually has finished primary moult, usually has a smaller p10 mirror (with subterminal band) and slightly longer legs.
Generally, baltic populations of HG can show a combination of red orbitals, yellow legs and sometimes even a solid p5 mark, making them difficult to separate from michahellis. However structure, moult timing during autumn, head striation, large white primary tips (also their spacing) and primary pattern if an open wing is seen, in most cases makes it possible to identify yellow-legged Herring Gulls against YLG.

 

[JayFeatherPL]

like 0 and 3 (argentatus, 0 also with yellow legs), birds 5, F and X also are late moulters, with a retained old p10 (and with a very large p10 mirror), unlike michahellis which at this time of year usually has finished primary moult, usually has a smaller p10 mirror (with subterminal band) and slightly longer legs.
Generally, baltic populations of HG can show a combination of red orbitals, yellow legs and sometimes even a solid p5 mark, making them difficult to separate from michahellis. However structure, moult timing during autumn, head striation, large white primary tips (also their spacing) and primary pattern if an open wing is seen, in most cases makes it possible to identify yellow-legged Herring Gulls against YLG.

And how can I tell if the primaries are old or new? Or if the primary moult has already ended or not yet?
Plus, are there any hybrids visible on the photos?

 

[lou salomon]

look at bird B (cachinnans): 4 white primary tips are visible (p6-p9, as p10 is lying under p9 and p6 usually is the first fully visible tip beyond tertials) - it has completed primary moult. all primaries are new.
take bird D (argentatus): 3 white primary tips are visible (p6-p8), so p9 and p10 still are growing beneath them - thus the whole wing looks shorter.
bird 3 (also argentatus) even shows only two white p-tips (p6 and p7) with p8-p10 being shed or growing.
birds 5, F and X (argentatus) have a retained old p10 (all white tip due to large mirror connected with white tip, also this white tip is very shaggy and abraded, visibly old), inwards there are visible two white tips of newly grown primaries which are the tips of p6 and p7 (so, p8 and 9 are shed or growing).

 

[JayFeatherPL]

look at bird B (cachinnans): 4 white primary tips are visible (p6-p9, as p10 is lying under p9 and p6 usually is the first fully visible tip beyond tertials) - it has completed primary moult. all primaries are new.
take bird D (argentatus): 3 white primary tips are visible (p6-p8), so p9 and p10 still are growing beneath them - thus the whole wing looks shorter.
bird 3 (also argentatus) even shows only two white p-tips (p6 and p7) with p8-p10 being shed or growing.
birds 5, F and X (argentatus) have a retained old p10 (all white tip due to large mirror connected with white tip, also this white tip is very shaggy and abraded, visibly old), inwards there are visible two white tips of newly grown primaries which are the tips of p6 and p7 (so, p8 and 9 are shed or growing).

Thank you