Search

The ability to accurately identify individuals is essential for both management and research of wild or captive animals. Marks need to be clear enough to be recovered, long-lived enough to provide useful information and not have health implications for the tagged animal which may affect survival. Substantial evidence suggests that more invasive, permanent marking techniques such as wing banding can cause injuries to bats, limiting the species with which such procedures can be used. Furthermore, low recovery rates can mean that the long term impacts of permanent marking on survival cannot be assessed. Here we present a new non-invasive, low cost approach to tag bats which can be carried out with the minimum of handling. Recovery of marks is simple and does not require handling. Our approach repurposes 'queen bee markers', small, coloured and numbered plastic disks which are commonly used to mark queen bees; instead they are affixed with superglue directly onto the fur of the bat. We carried out a pilot study at a large hibernaculum in West Poland, home to ca. 35,000 bats, the majority of which are Myotis myotis, the target species for this study. In November 2017 we marked 203 bats during a census of the underground fortification system. We recovered 30% of the originally marked bats over a time period of five months; 27% of the originally marked bats were identified to individual when resighted. Fifteen individuals were recovered in March that were not recovered in January, suggesting that they were either missed by recorders or were not present in the system during the census. Using the colour marking system allowed us to derive information about changes in bat behaviour when identification to individual was not possible, and individual identification revealed differences in hibernation strategies. We conclude that bee markers are an effective, cheap and less invasive approach for short term monitoring of bat populations and will also be useful to monitor whether recovery rates warrant the use of more invasive marking techniques. [ABSTRACT FROM AUTHOR]

In temperate regions, winter is characterized by cold temperatures and low food availability. Heterothermic animals can bridge this period by entering a state of torpor characterized by decreased body temperature and reduced metabolic rate. Hibernation site choice is crucial since temperature conditions in the hibernaculum will impact torpor. We analysed temperature-dependent hibernation site use of Barbastella barbastellus. Bats and temperature were monitored in an underground system (1999-2019) and standalone bunkers (2007-2019) in Western Poland. During the winter of 2017-2018 we analysed the thermal variability of the hibernacula. Seasonal variation is higher in bunkers and thus temperatures get colder in winter than in the underground system. On the other hand, short-term variability (thermal variability index) in the bunkers was lower than in the underground system. This makes bunkers a more stable environment to hibernate for cold dwelling bats in warm winters, when temperatures in the bunkers do not get below freezing. Bats use both the warm underground system and the colder bunkers. During the last decade, a continuous series of warm winters occurred and the population of barbastelle bats partly moved from the underground system to the bunkers. These present temperature increases broadened the range of potential hibernation sites for barbastelles. Our study indicates that long-term trends, seasonal variation and short-term variability in temperatures are all important and should be analysed to investigate hibernaculum use by bats. Our study shows that small hibernation sites may become more important in the future.