There were a lot of gulls on the beach at New Buffalo this afternoon, constantly getting re-shuffled by beachwalkers. Allen Chartier spotted this bird as I was combing the Ring-billeds for Mew Gull candidates.
The bird is about 2/3 of the way between Ring-billed and Herring in size.
Another look at the body size comparison between the CAGU and the RBGU as well as between the head shape of the HERG and the CAGU.
There were a lot of other gulls there, highlighted by 2 young Glaucous Gulls, and 3 different flavors of black-backed if you include Gull-nasty.