The Hill’s horseshoe bat, a critically endangered species, not seen in 40 years, was found again in Nyungwe National Park, a highly bio diverse area containing old-growth cloud forest.

The bat was rediscovered by a multi-national team of experts led by Bat Conservation International (BCI), Rwanda Development Board (RDB), and the Rwanda Wildlife Conservation Association (RWCA).

The rediscovery marked the culmination of survey efforts that took place in Nyungwe National Park and surrounding areas from 2013-2020.

According to the records published by BCI through the Global Biodiversity Information Facility (GBIF), bat species occurrence records resulting from survey data were collected as part of a long-term collaborative project to determine if the International Union for Conservation of Nature IUCN critically endangered Hill's horseshoe bat (Rhinolophus hilli) is extant.

Dr. Innocent Twizeyimana, Bat Research Coordinator at RWCA, was among the team of experts that rediscovered the bat.

He said that in January 2019, they dedicated a ten-day and night expedition to Nyungwe National Park as part of the project.

"We didn’t really know where the bat was,” he said. "We only knew the place where it was last found, but we were not sure if it was still there.”

"We would catch bats, investigate what they were and then release them. Later, we caught one and found out it was different. We then looked into the archival pictures that were taken when the Hill’s horseshoe bat was first discovered in 1981 and also tested that bat’s DNA. The results revealed that it was Hill’s horseshoe bat.”

According to the records, the researchers assessed all captured bats for age and sex as well as reproductive condition and measured standard morphometrics, including forearm length, tibia length, hindfoot length, tail length, ear length, tragus length, body length, and mass.

They also used a book "the Mammals of Africa Volume IV (Hedgehogs, Shrews and Bats) (Kingdon 2013)” as the primary key for species identification and then sampled skin tissue using a 3-mm biopsy punch from the wing membrane and stored skin tissue in desiccant until the DNA was extracted.

They also recorded voucher echolocation calls upon release for each echolocating bat species using an M500 full-spectrum bat detector at a sampling rate of 500 kHz. The DNA extraction from wing biopsy punches was carried out at CIBIO-InBIO, University of Porto, Portugal.

Members of the expedition spent long hours labeling their findings and reviewing their notes for unfamiliar species. / Photo by Jon Flanders, Bat Conservation International

Twizeyimana noted that currently, they know where the hill’s horseshoe bat lives but they still need to explore other parts of the park where the species can be found so that those parts can be protected exceptionally.

According to him, a continuous collaboration with BCI, RWCA and other partners is needed to find out more about the bat diversity in this incredible landscape of Nyungwe National Park.

Two other bat species were also discovered during the survey

According to the records published by BCI, two other notable species occurrences in Nyungwe National Park were detected, including the first record of Lander's horseshoe bat (Rhinolophus landeri) in Nyungwe National Park, and the first record of the Damara woolly bat (Kerivoula argentata) in Rwanda.

Jon Flanders, Director of Endangered Species Interventions at Bat Conservation International, told Mongabay, an environmental science and conservation news platform that the project couldn’t have been done without the Nyungwe park rangers, who found most of the caves and mist-net locations before the researchers arrived and have now recorded more than a quarter of a million audio files to survey for bat calls.

Speaking with The New Times, Protais Niyigaba, the Manager of Nyungwe National Park, said that the research has also found that the habitant size of the Hill’s horseshoe bat has increased, adding that the event has increased the park’s visibility since the species is listed by IUCN as critically endangered.

He declared that the occurrence also depicts a strong reason why the park should be highly protected, adding that the management keeps coming up with activities that help it generate income that contribute to its upkeep and benefit the surrounding community.