We use to plant corn with what is called a corn planter which was attached to the back of the tractor planting two rows at a time. The planter was calibrated to drop a corn kernel in the row so far apart from the last kernel dropped. We would finish planting and sometimes a crow or crows would come swooping down to where we planted the corn kernels. The crows would see where the corn rows were and walk over and find a kernel of corn. Then you would see the crow walk the exact distance to the next kernel in the row and pluck it right out of the ground. They did not need to grub around in the corn row to find the next kernel as they knew the distance on how far apart the next kernel was planted.