Bat Emergence/Re-entry Surveys

Bat emergence/re-entry surveys are undertaken at dusk or dawn between April and September, they identify whether bats are present within a structure and provide additional confidence in a negative survey result from a preliminary roost assessment survey if the building was identified as medium or high potential for a roost to be present.

The structure to be surveyed is surrounded by surveyors such that all potential entrance/exit points are covered. The structure is then watched from either 15 minutes before sunset to 2 hours after or 2 hours before dawn to sunrise.

All emerging or re-entering bats are recorded along with their flight path, their species and the time of flight.

An emergence survey would identify:

• Whether bats are present in a structure, the species and number involved
• Entrance and exit points for the roost
• The type of roost
• Actions needed to be taken to ensure legal compliance

All survey methodology follows that detailed in the Bat Conservation Trust's Bat Surveys: Good Practice Guidelines 3rd Edition.

A Soprano Pipistrelle (Pipistrellus pygmaeus) - bat flying close to a roost entrance

A listed building but also a Brown Long-eared (Plecotus auritus) bat roost