You'd have to email the facility for an answer to your questions on a couple of the photos. I would imagine that the birds of prey are untethered and put away for the night in an off-exhibit area as local dogs, foxes and coyotes would make short work of the birds if they were to attack them at night. However maybe the doors of the aviary are closed in the evening and perhaps the birds are then protected from predators. My guess is that volunteers and staff pick up each individual bird and place them safely in an enclosure every evening.
