Bat species activity measured at National Forest Inventory (NFI) squares, surveyed as part of the National Woodland Bat Survey.
The National Woodland Bat Survey is an England-wide passive acoustic bat survey conducted at NFI squares. Passive acoustic sensors are used to make ultrasonic audio recordings, and bat echolocation calls within these recordings are detected and classified to species using an automated machine-learning approach. The presence of each species at each NFI square is confirmed by manual review of call sonograms. In addition, a sample of bat species calls spanning a range of classification confidence scores are manually checked, and indices of bat species activity are corrected for the observed classification error rate.
Data are georeferenced using a delocalised grid. The bounding coordinates for each grid square are included in the dataset. Further information about the delocalisation process is provided in the dataset evidence pack. The data can also be explored on a map using the NCEA National Woodland Bat Survey Data Explorer (https://arcg.is/1mzTj13).
The 'National Woodland Bat Survey - Verified Dataset' is funded by the UK Government through Defra’s Natural Capital and Ecosystem Assessment programme (NCEA), with additional support from the Bat Conservation Trust.
Users should ensure they have read the supporting documentation before viewing or making use of the data. This includes the NCEA Analysis Ready Data Limitations Statement and dataset specific limitations/caveats outlined in the supporting documentation.
Attribution statement: © Forestry Commission & Bat Conservation Trust copyright and/or database right 2026. All rights reserved.
