This HUGE bird was roosting with a few other immature gulls in the parking lot. The first task would be to guess the bird’s age. There seem to be some gray patches showing through on the mantle, which would be the only indicator that this could be a 2nd cycle bird. Everything else points to a 1st cyle bird.
The nicely bicolored bill points to Glaucous (and away from Glaucous x Glaucous-winged) and the primaries are relatively dark grayish, yet maybe not brown enough for Herring. Please feel free to comment!