Atlantic Islands Gull

wooww...i'm not a expert, but thanks! I took this photos when I was in holidays...and this place is far from my home, is hard to study the birds!
Thanks for your share!

I have done some more research, the first picture is in fact a 3rd calender year Yellow-legged Gull, however, with the recent taxonomic update, as per Clements checklist v6.6 the scientific name is more likely Larus michahellis michahellis, the atlantis sub-species being restricted to the Azores? Also the Larus cachinnans has now been transferred to the Caspian Gull with the elevation to full species.

You do appear to have more than one species of Gull here, the darker ones being juveniles, they take 3-4 years to reach the full adult plumage. The term "seagull" is generic for all species, even though some are less associated with the sea than others. The one on its own has developed the adult bill yellow with large red spot which narrows it down to either Herring or Black-backed family, the dark colouration on top of the wings suggesting the latter, which would be lesser Black-backed Gull for Portugal, or Yellow-legged Gull if it is Herring family. Adults have all white tails, not sure if both juveniles show black on the tail. In the second picture, left and bottom look like Yellow-legged Gulls, middle right looks like juvenile Black-headed Gull, the other two I won't try to guess. Gulls can be difficult even for experts so don't be surprised to get different answers from different people. Its best to start with what you would expect to see in your specific location and study those species first and get to know and recognise the little differences, like wing tip patterns, bill patterns, leg colours, top of wing colour and head pattern.

It's possible, or, just the color it is diferent...

Wonderful in-flight photos. Looks to be at least two different types in the second photo.

Nice!