Hazeldene- A Successful Case of Bat Mitigation

Hazeldene- A Successful Case of Bat Mitigation

Proposed Works

The owners of this particular building wished to convert a detached garage into an independent living area. Bats were already known to be inhabiting the main building next door to the garage in overwhelming numbers so a survey and a European protected species licence was deemed necessary.

The Survey

The survey highlighted that the development of the building would mean the potential loss of a non-breeding soprano summer roost, or individual bats as well as the potential death or injury of bats that could be roosting during the development.

Pre Mitigation

Before the works began, Schewegler 2F General bat boxes were set up on suitable trees within the site, so as to provide a compensatory roosting site during the development of the building. A licenced bat ecologist was on site so as to give advice to the contractors, to supervise the removal of soffit boxes, ridge tiles etc so as to minimise and avoid harming/disturbing the bats.

Pre-mitigation bat box


The mitigation plan was also to ensure roosting opportunities were available for Pipistrellus species, external lighting was not put in place on the northern elevation of the property so as to create a dark corridor. Often external lighting causes major disturbances to bat populations as they are forced to alter their foraging sites and their behaviour accordingly.

Roosting was provided underneath barge boards on the northern elevation of the building and soffit bat roosts were also created that were positioned along the eastern and western elevation of the building as access to the roof would not be possible.

Diagram of a soffit box

Post Mitigation

Finally, further compensation will be put in place in the form of enhancing the landscaping around the building and designing the garden in way that will provide suitable habitat for bats such as encouraging night flying invertebrates. A swallow nest was also put in place to encourage the swallows to return to the area, a nesting bowl made of wood-concrete and a wooden panel of chipboard was inserted into the front of the building.


Overall, the site was a successful demonstration of how mitigation for bats can be put in place easily and efficiently without major disturbances to the bats or the client, with the combined co-operation of the client, surveyors, and contractors. 

Author: Ashely Dale