Long-Term Stability of Harvest Mouse Population

The Eurasian harvest mouse (Micromys minutus) is a tiny rodent of the Palearctic and Indomalayan regions, with a distinct regional species status in Europe and irregularly varying local numbers. We analysed the population of M. minutus in Lithuania (Northern Europe) based on trapping data from 1975 to 2022 and owl pellet data from 1986 to 2009. Based on both datasets, the proportion of this species in the small mammal community was similar, 1.13% and 0.62%, respectively. The proportions have remained stable across all decades. Relative abundance was 1.19 ± 0.19 individuals per 1000 trap days, stable over the long term and across the country. Irregular fluctuations in abundance were observed in some of the sites surveyed. The highest average RA was recorded in open sedge habitats, meadows and marshes. The absolute highest RA was 88 individuals per 1000 trap days in floodplain meadows after a major flood. Although the negative impact of habitat anthropogenisation has been confirmed, M. minutus does not require special conservation measures in Lithuania.