Gargoyles are nocturnal. They can't fly, but are very nimble. They are also skilled swimmers. Gargoyles attach themselves to buildings and remain completely still. Buildings generally have many gargoyles, but only one will be living and they prefer the highest buildings. They become active during storms and it they get hit by lightening they turn to stone and shatter when they hit the ground.
* photos courtesy of Arthur Spiderwick's Field Guide