I recently traveled through Vienna and saw European Ground Squirrel (souslik) and Field Hamsters.
European Ground Squirrels were on suburban fields between the railway stations Zentralfriedhof and Oberlaa, reasonably close to the airport. Two sousliks were seen, both on grassy strips bordering vineyards, which is said to be their favorite habitat. They were shy and binoculars were needed for good observation. Also seen were Swallowtail, two Scarce Swallowtails, Field Hare and Roe Deer. The nearby city cemetery Zentralfriedhof did not produce any hamsters, despite featuring in the BBC documentary. There were two unusually fearless Roe Deer. This is a vast area, and I did not even find likely burrows. I moved to the underground station Meidling and the Meidling Friedhof. It was much smaller urban cemetery, and I saw 6 Field Hamsters within 45 minutes, rather unafraid of people.
Hopefully, next summer travel will be possible for everybody, so below is the background information with useful maps. Apparently, sousliks live even on the airport grounds, although the best place is north of the city. Note that both rodents hibernate and are active only from about May to early August.