The current Bongo/Yellow-backed Duiker yard never housed rhinos, but has been home to a thriving group of Bongos for many years. Remnants of the once Black, and in earlier years White Rhino yard is adjacent to the Bongos, as you walk under the bridge that leads to the Red Ape Rain Forest. Just look for the large trees sitting in planter boxes.
@Blackduiker: I was close I guess. Thanks for the correction. I hope that the zoo gets back into the African rhino business at some point, but that probably won't happen for a long time, if ever.