Danger doesn't have to be noise. Dogs or flying birds out the window, or moving shadows, wearing a baseball cap - all these things scare my green cheek. Their senses are much more acute than ours and they are built to always be vigilant.
If he's not scared by something, he probably just wants to play/explore on the floor or get to something interesting.
How to fix? Well.. it depends why he is doing it. If he has a play stand, having it be high enough to make him feel like the big boss, having things on it that interest him - he can play here while he gets used to you. He'll want to play with you too, but sometimes you have to give them space. They are like us. They love attention and being social, but they need private time too. Play stand gives him a private place to be that isn't dangerous like the floor. Find out what makes him want to go to the floor and then make the play stand BETTER. Or make sitting with you BETTER! You have to replace the floor as the interesting place to be.
Adjusting behavior takes time. Just keep positively reinforcing the things that you like, and those will be the things he will want to do.