While visiting Sheboygan Wisconsin last month, I found this first summer Lesser Black-backed Gull working the surf about 100 yards offshore:
2nd cycle LBBG. Sheboygan, WI; 15 June 2012.
Note the two inner primaries that are darker than the rest of the wing - these are 2nd basic feathers. P3 is missing while P4-P10 are all first basic primaries that should be replaced some time between now and the end of the Fall season (perhaps sooner or later depending on several variables including hormonal state and ecological factors).
I imagine this species will be found summering more and more on the Great Lakes in years to come.