Daryl, could you give us a better explanation of your last three sentences. Another point, in Pennsylvania, the change from picking corn to combining it to ground level occurred at a period when pheasants just about disappeared. Is there a connection?
That scenario won't fly either, unless pheasants like less cover than more cover. Corn pickers left the shuck on the ear and put the whole ear in the wagon/truck to be hauled to the bins. Combines remove the shuck and cob from the ear, and only the shelled corn kernels are hauled out of the field, leaving the shredded corn shuck and cob on the ground. There is far, far more residue behind a modern combine than behind a corn picker.
