Okay, I'm not going to change your mind, but there are several open-fronted exhibits (bee-eater cliffs, argus pheasant forest floor and canopy, Asian rainforest destruction exhibit, Eastern North American woodland, Oropendola treetops) and two very large walk-through aviaries (African forest, South American forest). The artificial trees and living vegetation in all of the exhibits (except the hornbill treetops exhibits, which are rather sparse) are dramatic and lush. Although viewed through glass, the exhibits for Birds of Paradise, Red Bishops, Guira Cuckoos, Currasows are beautifully appointed.
San Diego's huge walk-through aviaries are obviously fantastic, but name some other US zoo bird exhibits you feel are better than the World of Birds