If you mean the black-headed gulls, after summer, they get their winter plumage and their head turns white but with a black spot on either side of their head.
At the moment, we are having an influx of waxwings, so you might see them in your area at some point.
Oh wow! Their colour change sounds amazing.
We had a bird book but didn't see the exact thing:)
I've only learnt this since blogging. 🙂
😁🤗