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Bats are seeking sanctuary in churches - but they're making an unholy mess
bbc.
This investigation must be conducted after sunset. As dusk envelops the cemetery of Guestwick Church in Norfolk, a team of researchers moves discreetly among the memorial stones. An old door emits a sharp creak, unveiling a cavernous and shadowy interior. Within, the team methodically deploys specialized monitoring instruments.
They position infrared and thermal imaging cameras and calibrate acoustic detectors to capture the ultrasonic frequencies used by bats for echolocation and social communication. Soon, the subjects of their study become active. Bats begin to execute swift, agile flights up and down the nave of the historic structure, their amplified echolocation clicks resonating in the space.
"Numerous churches have occupied these sites for approximately a millennium, and it is likely that bats have inhabited them for a comparable duration," elucidates Diana Spencer, a project leader for the Bats in Churches initiative.
A recent scientific study has corroborated that these ancient buildings function as indispensable habitats for various bat species. The research, published in the interdisciplinary journal People & Nature, derives from extensive surveys coordinated by the Bat Conservation Trust. It estimates that bat colonies reside in roughly half of all English churches—a figure exceeding 8,000 buildings. Among the most ancient ecclesiastical structures, this occupancy rate escalates to about 80 percent.
Spencer conceptualizes the churches as an anthropogenic analogue to a forest ecosystem. "They contain an abundance of small crevices and recesses suitable for roosting, expansive open volumes for flight, and dry, sheltered interiors," she explains. "This combination creates a remarkably optimal environment for them."
At Guestwick Church, two disparate species inhabit the upper rafters: Common Pipistrelles and Natterer's bats. The Pipistrelles exhibit crepuscular behavior, departing their roosts first each evening for a brief period of flight before exiting via minuscule gaps surrounding the main door. The Natterer's bats emerge slightly later, typically utilizing small apertures in the roof to access the exterior environment for foraging.
In the absence of specialized technology, observing these small, nocturnal mammals in such dark conditions would be virtually impossible. The study revealed that nearly one-third of the surveyed churches were entirely unaware of their resident bat populations. Conversely, in other parishes, the animals' presence is unmistakably evident, often through the detritus they generate.
"They are fascinating creatures, but they also present significant complications," states Graeme Peart, the maintenance officer for St Margaret's Church in Saxlingham, located near Guestwick. Peart recounts that the bats escalated into a considerable nuisance approximately fifteen years ago.
He enumerates the primary issues: "Urine and guano accumulation pose persistent problems. On one occasion, a carpet leading to the altar became so saturated with waste that it required disposal. Furthermore, their excrement has corroded and damaged brass fixtures and other ornamental metalwork."
In the United Kingdom, all bat species receive strict legal protection, making it unlawful to intentionally disturb, injure, or kill them. Consequently, St Margaret's Church collaborated with the Bats in Churches project to devise an innovative mitigation strategy. They constructed a fully enclosed loft space above the vestry, the room where clergy prepare for services.
Ecologist Phillip Parker demonstrates this specialized loft, accessed by ladder. "The fundamental premise is that bats currently roosting in the main body of the church will relocate to this dedicated space," he clarifies. The loft is equipped with closed-circuit television cameras, permitting continuous behavioral monitoring without direct human interference.
"Our observations indicate that during specific weeks, this loft may contain up to a hundred bats, which then abruptly depart en masse," Parker notes. "Their destination remains unknown, but they typically vanish for about ten days before returning. Without the CCTV system, this cyclical pattern would have remained undetected."
A major structural intervention like the loft at St Margaret's demands substantial time, labor, and financial resources. The construction and subsequent monitoring program incurred costs of approximately £50,000, funded through grants from the Heritage Lottery Fund and partner organizations.
Diana Spencer emphasizes that less costly mitigation measures are also viable. The Bat Conservation Trust administers grants for smaller-scale interventions. "Simpler approaches include deploying protective sheeting over vulnerable artifacts or applying specialized wax coatings to susceptible materials like brass to prevent corrosive damage from urine," she suggests.
She strongly recommends that any individual or institution discovering bats in a building should initially contact the National Bat Helpline for expert advice prior to undertaking any action.
Evidence suggests a growing number of bats are utilizing churches as surrogate habitats. "They are experiencing substantial loss of natural roosting sites, such as ancient woodlands and mature trees," Spencer observes. "Concurrently, we are demolishing old buildings and constructing modern dwellings that are warmer and more airtight, which further reduces available crevices and entry points."
This ecological pressure necessitates that church congregations cultivate strategies for coexistence with these nocturnal residents. Some parishes are reframing their bats not merely as a problem, but as an opportunity for engagement. "We increasingly observe churches organizing bat-watching events and educational programs," says Spencer.
She adds that such events can effectively foster connections with the broader community. "They serve as a compelling method to attract individuals, particularly local residents, who might not typically attend a traditional service but are drawn by the prospect of observing bats. People are genuinely captivated by these mammals," she concludes.