There are bison once again roaming Illinois prairies. It's been more than 175 years since the last wild bison died in this state, but as of October they are back, thanks to The Nature Conservancy project in western Illinois called Nachusa Grasslands. Chicago Tribune photographer Anthony Souffle has been covering the new Illinois bison and the restoration of the prairie on which they graze. When he returned recently to see their progress, Jay Shefsky tagged along.