Tonight we tried a different method. We wanted to know where she flies to when she leaves the box, but we can never see into the woods. So tonight, I'm staked out in the woods near where we lose her flight, and Julia is on the balcony watching. The plan is for her to call my phone when she is up, and for me to observe where she lands or flies.
She came up at 8:01pm, and Julia called me. She looked around quite intently in all directions, and then went back down at 8:14pm.
She came back up at 8:21, and left after about a minute of looking around. I saw her cross the power line clearing and head into the woods. This gives me a better location to begin looking for owl pellets, which may disclose the location of her perch.