My cat Storm is the smart one of my three. He's also learned how to open up the screen door. Once he opens it, the other two will run out. Luckily it's only a balcony on the second floor. I used to have plants out there and he liked to dig up my plants. He also likes to eat dry leaves that are out there. I always keep a spray bottle on hand so I can spray him when I catch him in the act. He knows he's not supposed to do this but he's like a kid. Oh well what can you do?