BLM Bat Fly-Out Inventory — Bureau of Land Management California

Out in Loraine, California, the BLM Bakersfield Field Office conducted a night outing at one of the local mines that has seen an increase in wildlife activity. The crew headed to the Amalie Mine where bats have been lurking deep inside the mine shaft. The mine was excavated in the early 1890’s for gold and silver and mines that are this old are typically designated to be collapsed for public safety precautions. However, because of the high number of bats residing in the mine, the BLM decided to keep the mine for habitat, but close it off to the public. Doing so this presented a great opportunity for the BLM Bakersfield Office to venture and see the bats in action.

BLM Bakersfiled Staff Member Romina Martinez testing out the night vision goggles

Over the years, many mines around California have been flooded with a variety wildlife species such as mice and small insects. Bats native to the region have been known to use these old mine shafts as roosting and nursery areas. Once it is determined that there are bats are within a mine shaft, “bat gates” are set up along the perimeter to help protect their habitat. The gates are furnished with steel bars running horizontally and vertically allowing enough room for the bats to pass in and out of the caves and inhibiting any hiker from entering. Its unique structure makes it difficult to see, allowing preservation of the historical appearance of the landscape and simultaneously reduces the hazards old mines contain.

The BLM Bakersfield staff knew that there was a significant amount of bats using the mining shaft near Caliente Creek Road at the Amalie Mine so a bat gate was installed to preserve their habitat. Though this gate was installed in early June, the staff felt the need to confirm these mammals were still in the mine shaft and that their environment was not completely disrupted.

Bat Gate at the Amalie Mine

On July 11, the staff planned a reconnaissance trip out to the mining site excavate and record any signs of bat activity. Eight employees from the Bakersfield Field Office and a local volunteer went, lead by wildlife biologists Amy Kuritsubo and Carly Summers. The trip began at 5:30 in the afternoon and ended at midnight so that crew could capture any of the bats’ nocturnal activity. At the site the crew separated into two groups, one group counting the amount of bats going out of the mine and the other counting the amount of bats coming in. To thoroughly monitor the site the crew brought along night visions goggles to navigate through darkness, a camera to help record any activity, and infrared lights.

The Mine Shaft where the Bats are located

The group set up their stations for the outing and positioned their camera towards the mine shaft. One of the unique tools they were able to utilize while at the site was the sonar equipment they brought along to help identify what lurked deep in the mine dwellings. The sonar equipment was used specifically to find out the bat calls echoing in the mine. Just like recognizing individuals for their pitch in their voices, bats are identified similarly as each species has their own distinct pitches that help differentiate each one from the other.

BLM Staff Setting up their cameras along the perimeter of the mining shaft

BLM Staff setting up their cameras along the perimeter of the mining shaft

The crew sat down with their gear at hand and waited attentively as the sun descended from the sky. Their patience was paid off as there was a flurry of activity later that evening. The clickers they had brought a long went off frequently as the amount of bats coming in and out of the mineshaft increased. With the amount of activity lasting up to two hours, they were able to identify roughly 200 bats coming out of the mine and 80 bats coming in without that time frame. An estimate of at least 100 bats were thought to inhabit the mine showing that this site was still occupied by the surrounding wildlife. With their sonar equipment, they were able to identify that types of bat species living inside was the Townsend Big Ear Bat.

BLM Staff wrapping the night up after an exciting night outing

With this truly extraordinary experience, the task was accomplished with exceedingly great results to follow. This information is pivotal for the future of this mine because it will help biologists track and monitor the bat populations throughout the region and better understand how to manage reclamation of old mine shafts similar to the Amalie Mine. The protection of these lands are more than just preserving the public lands for visitors to enjoy but also to protect the habitats of the surrounding wildlife who share this land as well.


Originally published at blmca.sites.usa.gov on August 6, 2015.

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