I'm gonna have to tell my friends up in the Chequamegon then. we had one Bur oak stand on the district and none of us ever went in there when the acorns were dropping. I think they'll have a bird when I tell them that.

Some of those are big, way bigger than we would ever find in WI. Acorns decrease in size with latitude. Not a perfect correlation but the trend is definitely there. It was reported here by a bunch of mostly bird biologists: doi.org/10.1139/B09-...

Latitudinal decrease in acorn size in bur oak (Quercus macrocarpa) is due to environmental constraints, not avian dispersal

The size of acorns produced by several species of eastern North American oaks decreases with latitude. We investigated three hypotheses for this pattern in the bur oak (Quercus macrocarpa Michx.) usin...