NDFF Monitoring wintering bats

This guide describes the method for counting the number of hibernating bats in objects that are easily accessible to observers, such as marl pits, bunkers, cellars, ice houses and forts. A standardised count is carried out annually by trained volunteers. The data is combined by the Dutch Mammal Society and, in collaboration with Statistics Netherlands, used to calculate population developments and trends. Dataset available via https://www.ndff.nl/english / [e-mail] Positive observations without zeros. 45,502 records (March 2018) https://www.ndff.nl/overdendff/validatie/protocollen/17-201-monitoren-van-vleermuizen-in-de-winter/