My apartment is tiny. Plenty of space up there. I was thinking of building them a house, put up some cushions all around that i would regularly wash, and let them call it home. There are planty of spaces where they can hide do its not a bare roof. But obviously I’m worried that they might jump off. The ledge is head high, but that doesn’t mean they can't easily jump on it. Would they be smart enough not to jump off the roof? Do they have some sort of built-in instinct where it would make it impossible for them to try to jump off high places they can't land safely?