@Baldur. This is the former Animal Nursery, opened 1969 and used for handraising mostly apes and other primates, one time a gerenuk.In 1986, the gorillas started as the last ape group, to raise their youngsters by themselfs, so the zoo used it after this time to keep permanent animals in it, mostly birds like macaws, cockatoos and other little parrot species. This house had also two apartment for the keepers,which have raised the apes.
This house is past now, they destroyed it to build the new ape house.
I think this was a nursery, and maybe sometimes had parrots in it as well. It was located on the south-eastern perimeter of the zoo (i think the road outside is called the Rhonstrasse). As far as I know, this is now gone, to make way for the excellent new ape house.