I'm positive most people that visit the Detroit Zoo regularly will agree that the "Pampas" habitat is the worst exhibit in the entire zoo. The exhibit as of recently has turned into a hodgepodge of animals from everywhere but South America. Right now the exhibit has fallow deer, sandhill cranes, one or two pelican species (can't remember which species), and an African spurred tortoise. All the true South American species have either passed away or have been transferred to a different zoo.
The entirety of the South American area in the American Grasslands is also lacking true South American species. The only two still at the zoo are giant anteaters and a greater rhea.