Joe Malyan

and 2 more

1. The severe decline of hazel dormice (Muscardinus avellanarius) is well documented and has led to increased legislative protection both in the UK and across Europe. Conservation measures for this species often include provision of nestboxes as a mitigation or enhancement technique after development projects. Previous research has offered some insights into how to select suitable general locations for nestboxes, but where to best place individual boxes to promote occupancy is less well understood. We hypothesised microhabitat variables related to proximity to food sources and nest building material will affect nestbox occupancy by dormice and should be considered when placing individual boxes within a selected site. 2. To assess individual nestbox occupancy by hazel dormice, 76 microhabitat variables were collected from 45 occupied and unused nestboxes in a deciduous woodland in Berkshire,UK. Variables were then used to predict probability of nestbox occupancy (observed from 2017 to 2021) using Random Regression models. 3. Results reveal nestboxes were more likely to be occupied by hazel dormice in sites with higher local cover and abundance of hazel trees (Corylus avellana), greater overall tree abundance but not fully closed canopies (best around 80-85%), more hawthorn (Crataegus monogyna) and honeysuckle (Lolium periclymenum), and when located further from footpaths. 4. Our results build on previous literature on habitat preferences of hazel dormice and importantly provide insight into relevant microhabitat variables that offer recommendations for where to place individual nestboxes to promote occupancy and facilitate recovery of hazel dormice.