Shedding Light on Bat Hibernation Assessments

Hibernation assessments for bats are often overlooked, but are a vital part of a bat roost assessment. Recently, Greenspace Ecological Solutions conducted hibernation surveys at two very different sites and would like to share the diversity of potential roosts.

One site was a classic hibernation spot—an underground tunnel, while the other was a 'non-classic' hibernation site—a dwelling loft space with accumulations of brown long-eared bat droppings. The use of laying white sheets on the floor during these surveys, to check for fresh droppings on the next visit, is a slightly alternative method but one that is an innovative way of saving costs for the client while still providing the answers we need. These bats, renowned for using the same roost site all year-round, highlighted the importance of considering seasonality and all roost types.

Examples of 'non-classic' hibernation sites range from industrial buildings to tall tower blocks in urban environments, boarded windows on derelict buildings, and gaps in brick/block/concrete on any building type.

The recently released 4th edition of the BCT good practice survey guidelines (2023) emphasises not overlooking buildings for their hibernation potential and avoiding automatically discounting 'non-classic' hibernation sites. The message is clear: Assess buildings/structures for their potential for all roost types. If your structure holds moderate or high potential for hibernating bats, consider hibernation survey effort, including inspections and acoustic monitoring across November-March.

Greenspace Ecological Solutions is here to offer advice on bat hibernation assessments or address any bat survey, mitigation, or licensing queries. Don't hesitate to reach out!