The Mouse-tailed Dormouse Myomimus roachi, probably the rarest dormouse species in Europe, occupies a special place in the continent's fauna. It has been known to exist for less than a century and its distribution is limited to Thrace with localities in Turkey, Bulgaria and eastern Greece. It is protected by the EU Habitats Directive. In 2017, Bulgarian researchers rediscovered the species north of the village of Levka, leading to an intensive monitoring programme. This includes the control of over 70 nest boxes and the placement of live traps in a 48-hectare study area characterised by dense shrubs and oak trees. This paper reports on a telemetry study carried out from September to October 2022 with the aim of calculating the home range of the species using the Minimum Convex Polygon method and Fixed Kernel Density Estimation. In addition, habitat parameters were recorded and their significant effects on the probability of catching the species were investigated using binary logistic regression. This study also analysed long-term monitoring data (2019 – 2022) to calculate an occupancy model and estimate the population size using the POPAN parameterisation. A Jacobs index was calculated using both monitoring and telemetry data. Population dynamics were analysed from the monitoring data. One individual could be captured for telemetry. The male’s MCP100 had a home range of 0.2252 ha, while the K65 had a home range of 0.1907 ha. This is rather small compared to other dormouse species. The Jacobs index showed a preference of the species for wooded and shrubby areas in the monitoring data and for open land in the telemetry data. The data showed a significant weight gain of adult males, juvenile males and juvenile females over the season, with an almost balanced sex distribution in 2021 and 2022, but males dominating in 2019 and 2020. The dominance of juveniles and adults in the population showed annual variation. The maximum population size was estimated at 77 ± 54 individuals in 2021. Survival rates ranged from 0.17 to 0.48, suggesting intense predation during hibernation. The occupancy model showed higher occupancy and detection rates than empirical data, highlighting the distribution of the species. The study also found that individual M. roachi can live for at least four years. The results suggest that qualitative variation in habitat may influence population reproduction and demography, while variation in sex structure may be related to sexual dimorphism in dispersal. Our findings conclude that the species acts as a boundary species between forest and open land, and the results provide important insights into the ecology of the species.