I had a cat (RB) that loved to push anything off shelves, especially at night. Books were his favourits, he even pushed a plant off which landed on my sister almost scaring her to death.

Maya had the telephone and answering machine crashing to the floor a couple of times, they are on one of her favourite resting spots and if she can't get comfortable she tries to push them off.

Smaller items are only safe on high shelves since Maya and Foxy like to push sthese off lower shelves and table tops. Prema does not bother with things like this.