[Studies on population of the bank vole (Clethrionomys glareolus Schreber, 1780) by Mark and release trapping in lower Austria].

1. Bionomical and ecological investigations on bank voles were carried out by mark and release trapping in two phytosociologically different areas in Lower Austria from 1963 until 1966. 2. The number of trappings and retrappings depends on the intensity of captures: 3 consecutive trapping nights in fourtnightly intervals appeared to be most favourable. 3. The life time of bank voles was determined as 3.1 and respectively 3.6 months in the two localities investigated. Only very few specimens reach an age of one year or more. 4. Bank voles prefer dense and covered habitats. 5. The home range of females has an average area of about 500 m2, that of males of about 2000 m2. Sexually active males may cover even larger home ranges of 3000 m2 and more. 6. The most abundant ectoparasites are larvae of chiggers and preadult stages of ticks, particularly larvae of Ixodes ricinus. The average infestation of bank voles with ticks is clearly correlated with the mobility of the former: more active individuals (males) are more highly infested. The density of infestation coincides with periods of maximum activity of the parasites.