Nature Hot Spot:
The city of Stuttgart offers plenty of opportunities for photographing wildlife. A very nice spot is a small pond called "Pumpsee", located in Rosensteinpark. The birds in this pond are quite used to people, and it offers a unique opportunity to capture close-up photos of species like e.g. the cormorant or the little grebe, that otherwise are very difficult to get close to.
Another spot for nature photography is Lake Max-Eyth (Max-Eyth-See), similarly offering the opportunity to photograph water birds, that may be more used to people here than you would normally expect in a less urban environment.