That's odd, that is enough space, you sure you know which one is the female?( No offense) but it's usually the females that lose their feathers due to mating. I still think that's the main reason for the jumpiness
That is another possibility but if it was a predator and they seem to be jumping all the time and every night I think there would be some evidence of something trying to get in after consecutive attempts. But it definitely could be fright from something. My Coturnix hop around quite often and I...
How big is the cage for them? Maybe they need a little bit more space. If the male is aggressively trying to breed with her that could possibly be the reason theyre running around and jumping to get at or get away from each other:) Maybe adding another female or 2 would do good. Just a thought...