Temporal and spatial activity of bank vole Myodes (Clethrionomys) glareolus and yellow-necked mouse Apodemus flavicollis in an oak-hornbeam habitat of the Bialowieza Forest

The aim of the study was to investigate the pattern of daily activity and connections between daily and spatial activity in relation to the forest undergrowth phytocenosis of the two most common rodent species - bank vole Myodes (Clethrionomys) glareolus (Cricetidae) and yellow-necked mouse Apodemus flavicollis (Muridae). The research was carried out in July 2017 in the oak-hornbeam habitat in the Browsk Forest District in the northern part of the Bialowiea. Forest. For rodents catching and vegetation evaluation the 1 ha study plot was divided into 100 squares of 10 x 10 m. Catches were made according to the catch-mark-release method. Wooden live traps (with bait and food for caught animals in the form of the grains of cereals, juicy fruits and aromatic fat) were set in the center of each square. The traps were controlled during 4 days at 3-hour intervals (0 a.m., 3 a.m., 6 a.m., 9 a.m., 12 p.m., 3 p.m., 6 p.m. and 9 p.m.). Traps occupied by rodents were marked with colored adhesive cards according to the established code. Twice a day at - 6 a.m. and 6 p.m. caught rodents were identified to the species and released next to the traps. The catch time was recorded. In total, 151 catches were registered. The daily activity of rodents was determined based on the total catches into assumed time intervals and at different times of the day (day, night, dawn/twilight). We provided a detailed description of undergrowth features of the area where rodents were caught. In each square we assessed the dominant species (on this basis the plants communities were established), the average height of vegetation and the degree of soil coverage with plants (undergrowth density). Collected data were used to the interpretation of the spatial activity of rodents in relation to the different undergrowth characteristics. The bank vole was distinguished by an even, day-and-night activity rhythm, while the yellow-necked mouse by monophasic - remarkably nocturnal activity. The dependence of the phytocenosis characteristics and spatial distribution of rodents was revealed for the daily activity of bank vole and twilight-dawn activity of both species. At dawn and dusk voles and mice were active in places with high vegetation. The density of undergrowth was the most important feature for bank voles during the day.