Ok You have a mouse in your tree, you have cats, I don't see the problem. The mouse will come out of the tree when you are not scaring it, or the cats will remove the mouse from the tree when you are not looking. Cats are hunters, cats kill things, mice are things cats like to kill. So you have to re-hang a few ornaments or the entire tree, just let your cats do their job. I live in the country and have 4 indoor cats, the life expectancy of a mouse here is about 8 seconds.
