Hazel dormice nest tubes
Nest tubes, similar to those first designed for use with edible dormice, can be a very useful method for detecting dormouse presence. The numbers of recorded nests or animals should not be used to infer population size.
It should be noted that the survey methods using nest tubes described in the Hazel Dormouse Mitigation Handbook (2025) and the Hazel Dormouse Conservation Handbook (2025) differ. It is recommended that the guidance given in the Hazel Dormouse Conservation Handbook (2025) should be followed in preference to that given in the Hazel Dormouse Mitigation Handbook (2005).
Putting up nest tubes
Correct installation of nest tubes is important to maximise the chances of detection. They should be secured in a horizontal position in woody and scrubby vegetation, selecting areas with the best habitat quality.
Tubes should be spaced approximately 15-20m apart along a transect, utilising the densest habitat. There is no benefit to decreasing the spacing to less than 10m apart.
Where nest tubes cannot be hidden in public areas use an alternative survey method such as footprint tunnels to avoid disturbing dormice.
In woodland
Tubes placed along ride margins and woodland edges maximise detection of dormice. Young plantations can also be surveyed using nest tubes. In mature woodlands, dormice may be active mainly in the high canopy, and this is likely to reduce the chance of detection.
In hedgerows
Nest tubes are often easy to place in hedgerows as there are usually suitable horizontal branches in dense vegetation. Tubes should be placed far enough into a hedge to avoid the flail line, or should be removed ahead of any hedgerow management.
In scrub
Dormice may readily use nest tubes in scrub habitats, especially when cover is reduced at the beginning and end of the active season. In rambling vegetation such as bramble, the tubes should be secured to several stems to ensure they remain level. Markers may be needed to find the tubes later in the season as there can be rapid growth of vegetation.
Timing of visits
Visit in the active season, from mid-late April to November. Monthly checks will give the best chance of detection.
Removing nest tubes
To preserve the wooden inserts and to avoid leaving plastic in the environment, nest tubes should be taken down at the end of the active season (usually by the end of November).
Recommendations for professional practice
It is easier to detect dormice using nest tubes in scrub habitats and hedges than it is to detect dormice in mature woodland.
The recommended survey effort for ecological professionals is to put up 50 nest tubes in scrub, hedgerows and dense coppice, and 100 nest tubes in high canopy woodland. These should be checked monthly throughout a season (Apr-Nov). If no evidence of dormice is recorded there is a greater than 95% chance that they are are absent. Once dormice have been detected, the survey can stop and dormouse population densities calculated as given in the Hazel Dormouse Mitigation Handbook P23 Sec 3.6.
Previously it was considered that if the number of nest tubes was increased, that could decrease the duration of the survey. That is no longer acceptable, each survey must utilise wither 50 or 100 nest tubes, depending on habitat type.
Please record both positive and negative results on the Nest Tube and Box Survey form.
Recommendations for conservation projects
Footprint tunnels provide greater certainty of detection of hazel dormice in hedgerow and scrub habitats and are more likely to achieve positive results within a shorter timescale, when compared with nest tubes and nest boxes.
If a demonstration of likely absence is not strictly necessary, fewer nest tubes can be used than as recommended for a professional survey. Suggested levels of survey effort (using footprint tunnels, nest tubes and nest boxes) are given in surveying in different habitats.
The level of survey effort, along with an assessment of the broad habitat type and whether dormice were detected or not, should be recorded on the Nest Tube and Box Survey form.
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