I found my earliest juvenile Ring-billed to date today. It was well inland, about 15 miles from the nearest "known" colony at Lake Calumet in Chicago IL. This is rather significant as juveniles haven't been reported closer to the lakefront colonies along Lake Michigan.
Juv Ring-billed. Tinely Park, IL; 16 June 2012.
I'm left with suspecting that there may be a closer nesting population than the lakefront. More to come on this later.