In the summer of 2021, we focused on the distribution and population size of one of our target species – the critically endangered rock grayling Hipparchia semele. During the survey from June to October 2021, focused mainly on the newly established grassland areas at Dívčí hrady, we recorded 44 males and 28 females. Rock grayling occurred mainly in the vicinity of solitary trees or around the enclosure with the Převalský horses. In particular, males used trees for so-called perching: they sat on an elevated spot and set out for flying butterflies and other insects in order to find suitable females for mating. Unfortunately, we were not able to record egg-laying as we observed at the same site in the previous season. The reason is probably that turf in the lawn is more developed. The planned disruption of turf on small areas could again increase the attractiveness of the Dívčí hrady sites for the development of Hipparchia semele.