The research presented in this paper provides an insight into the behavioural ecology of mountain hares on heather moorland in the Lammermuir Hills of south east Scotland. We examine the seasonal and diel activity patterns using camera traps over a period of 12 months. The rate of camera detections was calculated for the different divisions of the 24h cycle (daylight, dusk, night and dawn). During autumn and winter (October – February), the activity pattern was crepuscular with greater activity at dusk than at dawn. Daylight activity was relatively low and there was a regular pattern of small peaks of activity during the night. In spring and summer (March – September), peaks of crepuscular activity remained evident but daylight activity was much more prevalent than during autumn and winter, and night activity was lower. We discuss the problematic definition of twilight and present an explanation for seasonal changes in the pattern of diel activity that is linked to the reproductive cycle of the mountain hare.

For downloading this dataset:
1. Ignore the 'Download dataset' button and click on the arrow beside 31 March 2021, to reveal the zipped folder - 'S1A.zip'
2. Click on 'S1A.zip' to start the download (it is a 9.82 GB file and so it will take a while).
3. (a) MacOS10. Once you have the completed download on your desktop, double click on the zip file and it will unzip to a folder called S1A.
    (b) Windows. Once you have the completed download on your desktop, it needs to be unzipped using the free software 7-Zip rather than the inbuilt archive software. This will release the folder S1A.
4. Within S1A are the data for the 12 months of the year. Within each month are the data for the five camera traps (C1-C5). Within each camera trap are the images for that camera for that month. These images correspond in their camera times to the related data analysis file: https://doi.org/10.5061/dryad.2bvq83bpx which recalculates the camera times relative to sunset or sunrise.