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Bat Surveys Ensure Safe Reroofing and Post-Work Recolonisation

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Bat Roost Mitigation Leads to Recolonisation

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Water & EcologyWater & Ecology

Industry

Conservation Programs

Location

United Kingdom

ECOSA supported a reroofing project for a Hampshire property and outbuildings where five bat species were confirmed roosting. Working under a European Protected Species Mitigation (EPSM) licence from Natural England, ECOSA’s mitigation strategy replaced lost day roosts and secured new long-term roosting features. A follow-up survey confirmed serotine bats successfully recolonised the site, demonstrating the project’s ecological success.

 

Challenge

Prior surveys showed that five bat species, including common pipistrelle, soprano pipistrelle, Natterer’s bat, serotine, and brown long-eared bat, used the property’s buildings for day roosts. A planned reroofing scheme was essential due to roof condition and a cluster fly infestation but risked destroying all existing roosts and harming bats. The entire roof had to be sealed, making it critical to offset the loss of roosts and secure permission for works under strict legal protection for bats.

 

Solutions

Working closely with the client, the ECOSA team devised a suitable mitigation strategy to ensure that new bat roosting features could be installed while ensuring they were able to achieve the intended outcome of their proposal. This included four modified roof tiles, two modified ridge tiles, a soffit box and four bat boxes within the trees onsite. This ensured there was a range of suitable alternative roosting opportunities to meet the requirements of all the species recorded at the site. The incorporation of these additional bat roosting features will be left in-situ for the foreseeable – providing long-term roosting opportunities for bats within the local area.

Additionally, National England approved a European Protected Species Mitigation (EPSM) license allowing the reroofing works to be undertaken legally. Therefore, all the reroofing works were conducted under the supervision of a suitably qualified ecologist and the roof deconstructed in a methodical manner to mitigate against potential impacts to individual bats.

Services Performed

The team completed a Preliminary Ecological Appraisal and roost characterisation surveys, followed by DNA analysis for species confirmation. They secured EPSM licence approval, designed and installed alternative bat roost features, and supervised reroofing works. A post-construction population monitoring survey was conducted to assess mitigation success.

Results

A year after works were completed, ECOSA’s monitoring confirmed serotine bats recolonising the site, clear proof the mitigation strategy was effective. The modified roof tiles, ridge tiles, soffit box, and tree bat boxes now provide a range of permanent roosting options for local bat populations. The project balanced urgent property maintenance needs with robust wildlife safeguards, ensuring compliance and ecological continuity for years to come.

 

5

Bat species protected with mitigation

7

New roost structures installed onsite and in trees

1

Year post-project recolonisation confirmed by survey