It would be very interesting to have raptors and parrots as habitat animals, you could overtop them with a mesh ceiling which could be re purposed as a way to avoid escapes from climbing animals as well. Larger birds like parrots and raptors would be great for this, and would also provide amazing opportunities for conservation education since they're so threatened worldwide and many, such as vultures, are very misunderstood. You could also probably repurpose 2 or 3 models and behaviors amongst them all. Smaller birds could be housed in exhibits. We have invertebrates, why not birds?