There’s plenty of gull sites on the web but I find many of them focus on birds that aren’t quite normal. I’m posting shots here that are pretty typical birds.
Ring-billed Gull:
Adult, winter
Adult, winter
2nd year, May
Great Black-backed Gull:
Immature, winter
First year, May
Herring Gull
Adult, June
Adult, winter (background bird)
Adult, winter
2nd? year, winter (2 and 3)
1st year, winter (wings stretched) (3)
Immature, May
Ivory Gull
Iceland Gull
1st year, Feb in flight (2 and 3) (landed and 2)
Adult, winter
Lesser Black-backed Gull
3rd? year, winter (flying away, 2)
Corrections appreciated.