Is this part of a walk-through exhibit? I am just imagining this bird behaving aggressively during the breeding season, although I don't know much about this species.
Yes they are in the walk-through, they are in the middle of some fenced path, with most other birds unable to get into their section unless they fly, leaving mostly the herons, darters and spoonbills that frequnt this part of the exhibit with them. They are mostly docile to other birds, well the ones that I have seen anyway.