An elusive colony of Southern lesser short-tailed bats, located in Fiordland's Murchison Mountains, appear to be holding steady at between 300 and 400 individuals according to recent monitoring results from the Department of Conservation (DOC). 

The Murchison Mountains bats were only discovered in 2018 using acoustic recorders and are one of just three known populations of the tiny New Zealand mammal. 

DOC Ranger Warren Simpson said it is great to get more information on the status of this species.

South Island lesser short-tailed bat in flight. Photo: Hannah Edmonds/DOC

“Bats are extremely vulnerable to predation by introduced predators like stoats, rats, feral cats and possums."

"They are only found in areas where there is intensive, regular predator control like the Eglinton Valley, or predator free offshore islands.” 

In the Murchison Mountains there is large-scale control for stoats, but not rats, so the bat population is still quite vulnerable, Simpson said.

The Murchison Mountains are also home to the threatened and nationally vulnerable Takahē.

An annual monitoring programme was established in 2022 thanks to a partnership with Te Anau-based Contract Wild Animal Control New Zealand Limited (CWAC NZL). 

“This DOC/CWAC NZL partnership allows us to increase our understanding of the bat population density and distribution, providing tangible benefits to the conservation of New Zealand’s bat species,” Simpson said. 

“New Zealand’s short-tailed bat/pekapeka is unusual among bat species due to not only hunting on the wing, but also foraging on the ground using smell and their keen sense of hearing to locate prey as they scurry about the forest floor on all four limbs." 

”They forage like little pigs rooting around in the leaf litter."  

“This unusual foraging strategy was only viable to evolve in bats due to New Zealand’s lack of mammalian predators prior to their introduction by humans." 

“The more we know about them, the better we’ll be able to protect them,” he said.