The playground at the water tower at the Windtenstraße is one of the many places in Vienna where wild European hamster occur. The animals here are not particularly shy and some are even fed by locals.
I checked this place and it is right in the middle of a residential park. A few blocks up is the Wienerberg and Teich (Otto Benesch), so the Feldhamster have to cross some built up and asphalted over areas before they reach the outskirts.