His "floor plan" is wide open- not enough cover & hides for him to feel safe- BPs hide most of the time in nature, & even when hungry, they're "ambush-predators", NOT active hunters. They grab prey that gets cluelessly too close to where they're hiding. Out in the open, predators like hawks (etc.) have BPs for lunch. Seeing him in his home is nice for you, but apparently it's not making HIM feel at home. Might want to add some fake foliage etc.