When I had birds that's precisely what they did. Birds typically like to be in the highest comfortable place in a room for instinctual reasons. In my apartments

When I had birds that's precisely what they did. Birds typically like to be in the highest comfortable place in a room for instinctual reasons. In my apartments at the time, that meant the tops of virtually any open doors. (They also liked company so they'd generally follow me from room to room and sit on top of doors along the way.) You really don't want ceiling fans... So, yeah. I made sure there was generally something on the floor below them. But the sides of the doors would need to be cleaned fairly regularly. I had cockatiels, and you couldn't "potty train" them. Birds also like to chew things sometimes, so you needed to keep a close eye on them or realize your damage deposit was going to take a hit later.