Bats and Churches Research 
Natterer's Bats and Churches Research, 2012-2014 
Natterer’s bats sometimes form large maternity colonies in churches, especially in East Anglia where they can cause problems. To address these issues and find practical solutions two research projects have been undertaken by the University of Bristol. The research was designed to show whether encouraging bats away from sensitive areas in churches can be achieved in a practical and ecologically sound manner. It should be stressed that all this research has taken place under licence, as the use of such techniques to disturb bats would otherwise be illegal. 
Natterer’s bats tend to fly within the body of the church, where they can deposit urine and droppings, sometimes damaging furnishings and fittings, a special concern if these are irreplaceable objects of national or international significance.  In some cases, large quantities of droppings can restrict the use of a church for worship or other community functions. 
Successful solutions need to be built on a clearer understanding of why Natterer’s bats select churches as roosts, how they use the building and how their use of affected church buildings could be changed. The University of Bristol is working with a number of partners to determine the roosting requirements of this species and evaluate management options that could help church users, at the same time as supporting the conservation of the species. 
Funded by Defra, the project aims were: 
To engage a variety of key stakeholders, gathering information on the issues that are most important to address, to ensure the research is relevant and that stakeholders understand and can comment on possible options 
To determine the key environmental conditions of occupied roosts to inform the creation of effective alternative roost sites 
To develop options that retain bats within churches but reduce problems such as the deposition of bat droppings and urine in sensitive areas 
To quantify the impact of management actions taken to deter bats or limit the damage they cause, on the welfare of a representative sample of the local bat population 
To determine the impact of the management actions taken on local bat populations and model likely population trends 
What has been learned from the research? 
The radio-tracking studies of Natterer’s bats that were undertaken throughout the research project have shown that the colonies studied were highly dependent on their church roosts, with little use of alternative external roosts (i.e. other roosts in the local area) observed. This demonstrates the importance of understanding how an individual bat colony uses a church, when attempting to manipulate its behaviour to reduce negative impacts on a church community. 
In the short-term trials in 2012, the Deaton deterrent appeared to be effective at preventing bats from using their original roost within the church, during the four days of deterrent use. Bat droppings collected below affected roosts typically reduced to zero, or near to zero, by the third or fourth day of deterrent use. We found no evidence that use of this acoustic deterrent affected the foraging behaviour of Natterer’s bats. 
At the churches which operated the extended trials of the acoustic deterrents designed for use at wind-farms, the bats quickly relocated to alternative roosting locations within the church when the deterrents were operated. There was no evidence that the bats habituated to the deterrents during their 15-days of operation. The use of the deterrents did not appear to result in the exclusion of bats from the churches over the period, with similar numbers of bats present throughout the trial, but they roosted in different locations. There were no discernible changes to foraging behaviour. 
The prototype UK model acoustic deterrents were considered to show promise but further development would be required. 
The use of directed artificial lighting substantially reduced bat flight activity in lit areas of churches. The flight activity of all species present in the churches where this approach was trialled was reduced. The response of Natterer’s bats was particularly strong, but common and soprano pipistrelle species were less affected. The response of bats to the lighting varied among the churches, most likely to do with how reflected light impacted the remaining “dark” areas within each church. As well as changes to flight activity within the church, however, the lighting was also observed to change the emergence and nocturnal activity of Natterer’s bats. Time of emergence became more variable and the length of time the bats spent foraging outside the church was reduced. The use of lighting over extended periods may potentially be detrimental to bat welfare and conservation. 
There was little evidence that bat boxes installed inside and outside the churches had been used by bats during the study’s experimental periods but droppings underneath the boxes suggest some have been used subsequently. It has been observed in other mitigation studies that it may take a number of years before artificial enhancements such as boxes are used. Within churches bats may choose to use other alternative known roosting locations in preference to these newly installed features. 
Tailored use of deterrents to change the behaviour of bats inside churches, to reduce their impact on congregations, may be an option for some churches that have difficult problems with bats that cannot be resolved by other means. The techniques tested were successful in changing bat behaviour to reduce impact of the bats on church communities, but some approaches also have tangible risks to the welfare or status of the colonies which are not fully understood and merit further investigation. 
With judicious use of deterrents, problems caused by bats in churches can be mitigated. Deterrents can be used to move roosting sites within churches and limit where bats leave their droppings and urine so that problems to congregations and to artefacts of historic and cultural significance can be much reduced. In order to protect Favourable Conservation Status, these deterrents will need to be used under licence from Natural England or the relevant Statutory Nature Conservation Organisation (SNCO). 
The full report on the Nattere's bats and churches research funding by Defra can be downloaded HERE 
A scientific paper on these findings was published in January 2016 in PLOS One, this is available by clicking HERE 

Management of Bats and Churches - a pilot, 2015 

This pilot project, commissioned by English Heritage (now Historic England) built on the previous research outlined above. The project researched and development management techniques to enable churches severely affected by bats to implement cost effective solutions which protect churches and heritage in ways which cause no long term detrimental impact on bat populations 
Key research findings were: 
1. Acoustic deterrents were an effective tool in reducing the impact of Natterer's bats on churches. 
2. Natterer's bat and soprano pipistrelle roost locations could be manipulated with acoustic deterrents in spring/early summer. 
3. Soprano pipistrelles eventually habituated to acoustic deterrents. 
4. Light deterrents adversely affected bat behaviour and trapped bats within their roosts. 
5. 'Boxing-in' roosting areas around bats' entry points into a church was found to provide a promising solution, retaining roosting space for the bats but preventing access (and therefore deposition of droppings and urine) to the rest of the church interior. 
6. The operation of techniques and equipment were refined to create a toolkit for the effective and safe management of bats in a church context (based on findings for Natterer's bats and soprano pipistrelles), including a guidance document on the use of deterrents and bespoke 'boxing-in' measures. 
A full report is available for download from HERE. 
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