The African Aviary is a favorite stop of mine. There two big bang concepts for zoos with relatively (or proportionally) small investments. They are Aviaries and Herpetariums. In either you can house and display dozens of relatively low maintenance species in what is really by zoo standards a compacted space, thus provided so much added value for the public. The Maryland Zoo has two Aviaries: African and Maryland. Which is by far one more than most zoos have! (Although the Woodland Park Zoo in Seattle has 5!).
I could spend all day in this one place just watching the birds and allowing them to watch me. With birds, it's always a two-way street. And birds are very curious creatures. Once they establish that you are not a threat they perseverate on the question: Are you a source of food? At least in aviaries! They know that humans bring food. You can miss understandings like this when you just rush through an aviary.
The species you will see in these photos include: African Spoonbill, Black Vulture, Hammerkop, Blue-bellied Roller, Hadada Ibis, and Von der Decken Hornbill...not necessarily in that order.