Damage to natural habitat forces bats in Miaoli to move

"Bats have been disappearing from caves ... because of environmental destruction."

Chen Chia-hung, bat specialist

The abandoned traffic tunnel on the banks of Wenshui Creek (汶水溪) in Miaoli County used to be home to more than 1,000 Formosan leaf-nosed bats.

But in recent years, large numbers of the bats have disappeared because of a sharp drop in the amount of water in the creek and because of drastic fluctuations in temperature.

On a recent inspection of the caves, Chen Chia-hung (陳家鴻), a bat specialist from Miaoli's Shei-pa National Park, discovered that there was only one bat remaining in the tunnel.

He suspects that unstable moisture conditions and variable temperatures prompted the bats to find another cave in which to pass the winter.

The tunnel is located on an old trucking road that connected Miaoli City and Shihtan Township (獅潭鄉) during the Japanese colonial era.

But the road gradually fell into disrepair after the opening of Provincial Highway No. 6.

Falling from typhoons eventually blocked off the openings of the tunnel.

Chen's joke that he is nocturnal himself because of the long hours he has spent researching the creatures over the past eight years.

He was working towards his doctorate in biology at Tunghai University when local residents first invited him to investigate.

He said that the Formosan leaf-nose is indigenous to Taiwan and feeds on insects.

Based the droppings he found, he estimated there used to be more than 1,000 bats living in the tunnel.

However Chen said that the disappearance was not unique to Miaoli.

"Bats have been disappearing from caves where they used to be common all across Taiwan because of environmental destruction," he said.