Young gulls are annoying.
The Black-Headeds are fine, but the 1st/2nd year 'larger gulls' - Herring, Yellow Leg, Lesser Black-Backed - all seem to look identical in my bird books. Got some good views of what I'm pretty sure was a second year Herring yesterday lunchtime, You could see the back was starting to lose its brown feathering and pale grey was showing through underneath. The Gull was very obliging and, while I was watching, helpfully stood next to some Black Headed Gulls so I could compare greys (which were very similar) and a Lesser Black Backed so I could compare size (practically identical). It was also behaving in an interesting way and trying to eat some of the crap that litters the bed of the Thames (including one thing that looked like an inner tube), so plenty to see.
I do like Gulls. Even if you see them everywhere, they do interesting things and are fun to watch, and tend to have a bit more character than other birds. I just wish they'd come more clearly labelled.
I think next month's paycheck may have to be invested in some kind of specialist Laridae book...