How Volunteers and Radio Tags Are Helping Protect Scotland’s Bats

Citizens are increasingly interested in seeing bat populations, and the habitats they rely on, thrive.

THE SMALL BAT has long, nearly transparent ears drawn back against its body and fur that shines golden brown in the glow of our headlamps. The bat’s tragi — fleshy projections which cover the entrance of the ear — poke downward like a second pair of ears. Its feet firmly grip the damp, stone ceiling. Its wolfish face hides behind a fold of wings through whose thin membrane one can see veins glowing like tiny pink rivers.

bats in scottish night sky
Scotland is home to 10 bat species. As in other parts of the world, bat populations here have been experiencing a massive decline over the past century. Photo by Stuart Anthony

I lean forward, careful to keep my hardhat from scraping the low-hanging ceiling. Loose slate clicks underfoot and echoes down the passage as I move in a slow circle around the bat, enthralled by the tiny creature before me.

This particular bat hangs about two hundred feet from the small, square opening of an abandoned mine shaft in Aberfoyle, Scotland. Mounds of disused slate slabs create a unique geographical landscape above us. Until the 1950s Scotland used its own slate, making Aberfoyle one of the most important quarries in the country, but today, the caves are abandoned except for the bats, who’ve settled there for the cold winter months.”

“This one is a long-eared bat,” says John Haddow, Scottish bat specialist since 1974 and our guide for today’s hibernation count. Haddow, who has sharp blue eyes and a shock of white hair on his head and his chin, peers through his horn-rimmed glasses as he marks a small X on a drawing of the cave we’re currently crouched in. The mark will be recorded and sent to the Bat Conservation Trust (BCT), the United Kingdom’s leading organization for bat conservation, where it will become part of data from multiple hibernation counts like this one that are being done to determine if bat populations across the country are recovering.

As in other parts of the world, bat populations in the United Kingdom have been experiencing a massive decline over the past century. Many bat species around the world are vulnerable or endangered due to factors ranging from loss and fragmentation of habitat, diminished food supply, destruction of roosts, exposure to chemicals used in construction, disease and hunting. Scotland is home to 10 species, five of which are considered to be common or widespread. These are the common pipistrelle, soprano pipistrelle, Daubenton’s bat, brown long-eared bat and Natterer’s bat. The rest are considered rare or occur only in specific areas. Nearly all these bats are classed as European protected species.

“Be careful not to shine the light on the bats for too long,” Haddow says as we duck and continue down the dark tunnel. “We don’t want to disturb them for any longer than we have to. The light and the noise may wake them up.”

We move slowly, careful not to brush up against any bats hiding in the shadows. At the beginning of the tunnel, we had to wade shin-deep through sediment-clouded water. Now, the water is a mere trickle underfoot. “What signs are we looking for?” I hear someone behind me ask. “Will there be any droppings or signs of feeding?”

Haddow shakes his head. When the bats begin their hibernation in the month of November, their metabolisms slow to conserve energy. Their heartrates decrease from a usual 200 to 300 beats per minute to as few as 10 beats per minute, while their body temperatures drop by 60 percent or more. The bats in Aberfoyle won’t emerge until March or April, when the temperatures outside are warm enough to bring moths to their front door.

“You’ll want to check the crevices that are only a few centimeters wide.” Haddow tells us, demonstrating by holding his fingers slightly apart. “The Natterer’s like to fit themselves in there — look.” He shines his flashlight into the cracks of slate along the wall. Squeezed into small space in the gray stone is a hibernating bat, its wings tucked close to its body.

We spend nearly an hour searching the tunnel in two groups, checking each stone and crack for the telltale glimpse of a tiny, wrinkled face or a dark folded wing. We make note of the few that hang from the slate ceiling. Among them, we count three Natterer’s, four long-eared, and a single Daubenton’s bat.

Haddow identifies the Daubenton’s. According to him, the easiest way to tell the difference between a Daubenton’s bat and a Natterer’s bat is the fur behind the ears. “I have a photograph here I took during the summer,” he says, pulling a color print from the papers on his clipboard. It’s a roost of bats, hanging closely together on a metal grate. “That’s 12 Natterer’s bats up at Doune Castle. You can see what I was talking about with the identification. See the pale bit behind the base of the ear?” He points to the light fur behind a few of the bats’ ears. “That’s how you tell it’s a Natterer’s and not a Daubenton’s.”

IT WAS THE MORE EASILY found common pipistrelle and soprano pipistrelle bat species, which can often be seen flitting about near dusk in search of midges and other flying insects, that initially drew Elisabeth Ferrell, Scottish Bat Officer at the Bat Conservation Trust, to these flying mammals. Ferrell became fascinated with these animals at just 15, when her family took a family holiday to Wales and stayed in a small cottage.

“We were just chatting, having a quiet night in,” she recalls. “I saw the first few bats clip past the window outside, and I got so excited.” We’re sitting in her office on the second floor of a The Conservation Volunteers building that houses several nonprofits. To the left of her desk hangs a poster of bats of Great Britain and Ireland. Behind her is another poster of a bat in flight. Across from her desk is a large map of Scotland, its surface littered with colored tabs highlighting various bat records such as roosts, echolocation recordings, and visual sightings that have been shared with her verbally.

“I had never seen a bat that close,” she continues. “So, we went out and realized it was a roost emerging from the cottage. They were swooping out from the roof and right along the wall, past the window. I stood next to the wall so that I was obstructing them almost, just because I wanted to be that close, and they would just wisp past me. I just thought, ‘That’s amazing. It’s pitch-dark and they know that I’m here.’ They saw me and then changed their direction so quickly.”

After that family holiday in Wales, she threw herself into studying bats, getting her bachelor’s degree in zoology from University of Glasgow, and then an internship with the BCT in London. “Before that,” Ferrell tells me, “I was probably like most people. You never see them, so you don’t really think about them. Bats are mischievous, misunderstood animals, and I think that’s what I love.”

As I left the interview, Elisabeth’s words stayed with me. Before experiencing bats up close, I thought of them as isolated cave-dwellers, if I thought of them at all, and I’m not alone. Except in China, where they have long been celebrated as symbols of good fortune and happiness, bats are commonly associated with fear or disease. In reality, bats can be found in almost every habitat in the world. They impact everyone, playing a vital role in the environments around them. Pipistrelles, for example, rarely grow longer than two inches, but can eat up to 3,000 midges in one night and tend to roost where there are large amounts food (read: insects), balancing delicate ecosystems. They act as a natural pest-control and keep bugs away from crops.

Though changing landscapes have caused bat populations in Scotland to decline considerably over the past century, it appears that local measures to protect them are slowly bearing fruit.

Data collected through the hard work of people like Ferrell and Haddow, as well hundreds of volunteers, confirm that current legislative and conservation efforts are having a positive impact on bat populations. Surveys in Scotland, for instance, showed that populations of the threatened common pipistrelle had increased by nearly 80 per cent from 2009 to 2015.

Collecting that data, however, hasn’t been easy. Counting bats is tricky business, especially during hibernation periods. Because bats hide in cracks, counts can often be significantly off. To counter this, the Bat Conservation Trust not only tracks the consistency of data collected by dedicated volunteers from year to year and compares population trends, but has also found a way to tag and track the movements of bats using Nanotags, the world’s smallest coded radio transmitter. Weighing only a quarter of a gram, these tools can be safely glued to bats that are captured and then released. This process is labor intensive, though. Because there is no battery small enough for GPS tagging, the signal needs to be manually pinged by someone out in the field.

“It’s a lot of late nights,” Ferrell tells me with a laugh, but to her and many others, the results are worthwhile. Thanks to this technology, researchers and conservationists are now tracking new roosts and hunting patterns, all of which will help to determine what areas need to be protected for future generations of bats.

“It’s all about increasing our knowledge,” Ferrell tells me. “There is a large and growing voice for change in this country with people wanting to see bat populations, and the habitats they rely on, thrive. The more we learn and communicate about bats, the more we strengthen this call for change. Ultimately, we want bats to be around for our children, so they can look up in wonder as bats dart and dive, catching their insect prey. We have so much still to learn about these animals; it would be heart-breaking for them to disappear from our night skies.”

I think of the excitement I felt in the caves as I spotted my first bat nestled in stony cracks in the wall, its closely folded wings, and tiny wolfish face illuminated in the narrow beam of my flashlight, and I know Harrow and the volunteers would agree with Ferrell. Future generations deserve the chance to see bats, to experience the same feelings of amazement and wonder I did that day, and appreciated bats as essential participants in our ecosystems rather than winged pests.

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