I've also been wondering which areas of the world have black or dark eyed gulls. I haven't heard of them here in Australia, but a quick internet search hasn't helped much because they seem to be in a lot of places in Europe and North America. A quick search might have narrowed them down to being either Herring Gulls or Caspian Gulls.

I'm also thinking that the similarity of the sound of "gull" and "girl" might lead to northern English areas but I could be way off with that idea. Mudcatters from the UK will know. I'm only basing that idea on the accents I hear on UK TV shows.