They are Ural owls, Central European subspecies. They are headed to forest near Vienna.
Some countries (Austria, Germany, Czech rep.) are reintroducing this species at seveal different locations. In future, they should inhabit again an area where they have been extirpated - old forests and woods between nothern slopes of Alpes in Germany, through Bavaria, whole Austria, south Czechia and create one unterrupted population all the way to western Ukraine.
Thankfully, intensified protective measures impelemented in late 20th century in areas where the species survived naturally like south Poland and mountains of Slovakia, has started a slow natural bounce back, independent of artificial introductions. Ural owls, on their own, managed to spread to most of Slovakia, are underway in east Czechia (first breeding announced in Jeseníky mountains last year) and spread to some new lowland forests in south Poland.