The rediscovered brown long-eared bat enjoys the spotlight. Credit: Fiona Mathews
On the final night of Fiona Mathews’ bat sleuthing expedition, she hit a species jackpot. Nestled in her trap was a pregnant brown long-eared bat, a creature thought to be extinct from the Isles of Scilly where the bat team had spent the last four nights. No one had seen a brown long-eared bat on the islands since the 1960s, and locals assumed the population had died out after their habitats succumbed to development. Mathews took one look at the tiny critter and realized the magnitude of the discovery. “As soon as we saw her we were very excited,” she says.
Mathews, a mammalian biologist at the University of Exeter in England, arrived on the scene after the Scilly Isles Bat Group sent out a call for help to the mainland bat experts. The Isles of Scilly are located about 40 miles off Land’s End, or the southwest tip of Great Britain. The islands sport an almost subtropical climate and are famous for their remarkable flowers and propensity to wreck ships. The archipelago includes five inhabited islands along with lots of rocky outcroppings, and only about 2,000 people call them home. The next closest western stop to the remote Isles is the United States.
The bat team’s mission was to seek out as many bats as possible. Locals feared that a single roost was used by the only known population of pipistrelles, the smallest and most common type of bat in the UK. If anything were to happen to that roost, Mathews explains, the bats would be gone. But to the team’s pleasant surprise, they immediately began uncovering whole series of roosts that nobody had known about, and even other species. “Even though the pipistrelles were roosting in buildings where people lived, the people didn’t know they were there,” Mathews says, “They really are secretive creatures.”
Fiona Mathews cradles a bat. Credit: University of Exeter
Finding the elusive brown long-eared bat proved to be more of a challenge. To undertake the feat, Mathews had to use a special contraption called a harp trap. Also known as the “whispering bat,” the species relies less on echolocation than other bats, so typical sound detectors don’t do the trick. The harp trap (which resembles the instrument for which it’s named) is composed of a series of offset strings made of fishing nylon. A flying bat that collides with the strings will slide down into a collecting bag, unharmed. On an avenue leading to the local church, Mathews caught her brown long-eared bat using this method.
Brown long-eared bats are found throughout Europe and make their home in woodlands. Their distinctive ears are three quarters the length of their head and body. The animals use their huge ears to detect the sounds of caterpillars and other insect prey on leaves.
They tend to be homebodies, not venturing more than a mile or so from their roost.
Brown long-eared bat from 1884. Credit: RA Sterndale
Researchers are especially excited about the bat’s pregnancy since it indicates that there’s probably a colony nearby. “We don’t know for sure, but it would be very unusual to have a breeding female in isolation,” Mathews says. She explains that mother bats generally have their babies in groups so they can huddle together and collectively keep the young warm.
In just four days, Mathews and her team re-discovered a lost species and found that Scilly hosts not one but three types of pipistrelles. “We really were amazed at the diversity we found,” she says, “and that such a range of species would be found on such small islands.”
In addition to carrying out more field surveys to get a handle on the state of the bat populations, local conservation is needed to ensure these species can thrive. Increased habitat could be a starting point. Trees, the brown long-eared bat’s choice home, are in short supply. Few trees are left on the islands, and those that do grow there were planted years ago and are reaching the end of their lives. The archipelagos are very, very windy, Mathews says, “which makes life hard work if you’re a bat with no shelter.” This means habitat management like planting trees could really give the bat populations a boost. Things like bat houses would also be a plus, as well as making sure insects—the bats’ food—are bountiful.
Belinda the bat poses for her close-up. Credit Fiona Mathews
As for the female bat, researchers on the island have kept their eyes on her in the hopes of finding her fellow brown long-eared bat friends. And she seems to have won the hearts of Mathews and her team, too. “It was funny because all the names we could think of were boy names, like Boris or Bert,” Mathews says. They finally settled on Belinda the Bat.
See also: Vampire bats, Deadly bat disease, Bat-watching, Bat houses, How to remove a bat from your house