Coons.... Knock down the stalk, take one bite and go to the next. We tried to teach them how to tell when the ears were ready but they just didn't catch on.......... So, I put a post in the ground, Put a motion detector double flood light unit on the post with a flood in one side and plugged a radio in the other side (wrapped in a plastic bag) and other than the wind and rain setting it off we can tell when something is in the garden. Set the motion detector to test and it will come on and off only when it sees motion. Our critters seemed to like Country so we had to set it to Rock.
For the rabbits, we plant a few Habenaro pepper Plants each year and dry the peppers over the winter and put them in the blender in the spring to grind up. Then we use an old cheese shaker to spread around the edge of the garden. They stay out... I have also heard of people putting pepper on the ears and around the stalks. I prefer butter and salt on my corn.
I had an old fellow tell me once he went to goodwill store and got a bunch of old socks to cover each ear and then put a drop of perfume on each sock. I still get a chuckle thinking of him telling the story............... Tom