Dormouse Survey Devon

Investigating the Use of Artificial Nest Boxes for Dormice: Implications for Survey Guidelines

Introduction

In a recent study, scientists investigated the effectiveness of artificial nest boxes for dormice surveys.

The hazel dormouse (Muscardinus avellanarius) is an arboreal mammal, primarily active in the trees and visiting the ground mainly for winter hibernation. The common method for surveying dormice involves placing artificial nest boxes at approximately 1.4 meters above ground level. This study, conducted in two phases, aims to evaluate the effectiveness of this method and its implications for current survey guidelines.

Phase 1: Nest Box Positioning

  • Objective: To assess whether the height at which nest boxes are positioned affects dormouse occupancy.
  • Method: Artificial nest boxes were positioned both high in the tree canopy and at the standard height of 1.4 meters on the same trees.
  • Findings: Dormice utilized both high canopy and standard height boxes, indicating that they do not strictly prefer one height over the other.

Phase 2: Isolated Positioning

  • Objective: To determine if dormice will use nest boxes placed in isolated positions without arboreal connectivity.
  • Method: A third set of nest boxes was placed on isolated posts with no connection to tree branches, conducted at a different site.
  • Findings: Dormice were found to use isolated nest boxes, suggesting that they can traverse open ground to some extent.

Implications for Survey Guidelines

The findings from both phases suggest that the current survey method, which primarily uses nest boxes at 1.4 meters, might not be fully reliable for determining the presence of dormice. Dormice’s use of nest boxes at various heights and isolated positions indicates that surveys should include a variety of nest box placements to increase detection accuracy.

Long-Term Survey Insights

  • Observation: The use of artificial nest boxes declines over time.
  • Implication: This decline has often been interpreted as a population decrease. However, alternative explanations, such as the dormice’s preference for newer boxes or habitat changes, should be considered. Further investigation is required to understand this trend.

Conservation Recommendations

The apparent decline in hazel dormouse populations and their range contraction, as shown by current surveys, necessitates a review of the survey methods. The study suggests:

  1. Inclusion of Multiple Heights: Surveys should place nest boxes at various heights, including in the tree canopy and closer to the ground.
  2. Isolated Box Consideration: Incorporating isolated nest boxes could provide a more comprehensive understanding of dormouse presence.
  3. Long-Term Monitoring: Regular replacement or maintenance of nest boxes to prevent decline in usage due to age.

Conclusion

This research highlights the need for revising current survey guidelines to ensure they are robust and accurately reflect dormouse populations. By incorporating a more diverse range of nest box placements and considering long-term usage patterns, conservation efforts can be better informed and more effective.

For more information on this study, please refer to the original research article published in British Ecological Society

For assistance with dormouse surveys please contact Acer Ecology Ltd on 02920 650 331 or enquiries@acerecology.co.uk