@vogelcommando I've been looking for matches and I feel Finsch's Parakeet might be the best match based on the white around the eyes and the red on the forehead (might be hard to see in this picture). I'm just not sure how common that species is in captivity, although Monkey Jungle did at one point import rare species from the neotropics so this could be a surviving holdover from that time. What do you think?
Could be but if we believe Zootierliste the Finsch's parakeet isn't kept at US-zoos anymore but at least in Europe it's kept and bred in small numbers in the private sector. The Aratinga's are quite a difficult group to ID and also a number of hybrids are around. Next time you are at Monkey World try to make some more photo's which show the bird from different viewpoint. Maybe then a 100 % ID will become possible.