The dominant oak species out at Allerton Park & Retreat Center are white oak, northern red oak, black oak, bur oak, and shingle oak.
Dominant hickory species include shagbark, bitternut, and mockernut.
My take on this is simple: east-central Illinois is experiencing an above average to "bumper crop" mast year for certain hardwood species. This is especially the case for northern red oak (Quercus rubra) and the urban pin oak trees (Quercus palustris).
I've discussed the concept of masting and bumper crops via previous postings -- please feel free to read through those responses!