Going batty at Barnum Cave

Annual public tour provides up-front experience

A closeup of a Townsends big-eared bat.

Barnum Cave is the winter home, or hibernaculum of a small colony of Townsends big-eared bats, which prefer lava tube caves. The female bats arrive first in early Fall, then the males. The cave temperature remains in the high 30s, and is very dry. When the temperature warms in the spring, the bats, including the now pregnant females, depart for their summer habitats and nursery colonies. Credit: Ann Froschauer/USFWS


By Susan Sawyer
October 31, 2019

It was a dark and stormy fall night in a pine-juniper forest of rural northern California. A group of 30 visitors had carefully made their way about 200 yards inside Barnum Cave, located off an unmarked dirt track halfway between the towns of Yreka and Weed.

Liz Wolff holding a bat skeleton in a clear case.

Liz Wolff is one of a group of northern California cave and bat experts who partner with the Service to lead a guided public tour in Barnum Cave each Fall. Here Wolff displays a bat skeleton. Credit: Susan Sawyer/USFWS

“Everyone needs to lean on the wall or sit on a rock, then turn off your headlamps,” said Liz Wolff, a member of the Shasta Area Grotto of the National Speleological Society (those who specialize in the study of caves).

For the past seven years, Wolff, along with fellow cave enthusiasts and bat experts, have partnered with the U.S. Fish and Wildlife Service and the U.S. Forest Service to lead this annual public tour into the underground world of lava tubes and bats.

“Once the lights go out, don’t move,” cautioned Wolff. A few seconds after uttering those ominous words, the group was enveloped in complete and total darkness. “Now we wait,” said Wolff.

With reassuring but disembodied voices in the dark, Wolff and biologists from the Services’ Yreka Fish and Wildlife Office and the Klamath National Forest then provided bat facts and a geologic timeline of Barnum Cave. Sam Cuenca, with the Klamath National Forest, asked for silence as he turned on a small handheld meter. A series of rapid clicks and chirps grew loud, then faded then became loud again.

“Those are bats, and they’re checking us out,” said Cuenca. “There are at least two, probably Townsend’s big-eared bats which are the most common here. They’re flying all around us.”

Two Townsends big-eared bats hanging upside down.

Just hanging out – Townsends big-eared bats are the most common species to use Barnum Cave, primarily during the winter months. These bats hunt insects about 4 – 6 feet off the ground, and prefer beetles and moths. Photo courtesy of Dave Bunnell/Under Earth Images

Upon hearing this, a few audible gasps rippled through the group. One youngster excitedly whispered “there’s one flying in front of my face.” Others said they could feel the slight wind of wings as the bats fluttered silently around.

Bats may not be caped crusaders, but they certainly possess a superpower – echolocation, similar to that of dolphins. The clicking sounds heard on the sonar detector were the bats bouncing ultra-sonic sound waves (inaudible to the human ear) off the visitors.

“This is how bats communicate with each other, and find their food at night,” said Wolff. “Bats in this area eat insects, but tropical bats eat fruit, or even small birds and frogs. Most bats hunt in flight, while others will hunt on the ground or in trees and shrubs.”

After a few minutes that seemed to last an eternity, the group turned their headlamps on. Service biologist Jen Jones continued the discussion on bats, saying they have gotten a bad rap in the past, and even today are commonly associated with comic book superheroes or blood-sucking vampires. In fact, bats are a critical part of nature’s ecosystems.

“Bats aren't blind, don’t take human form and only three species - none of which live in North America - feed on blood,” said Jones. “Bats are shy, intelligent creatures that make up one-quarter of the Earth’s mammal species. They help in controlling insect pest populations, provide fertilizer (guano) and help disperse seeds in forests, deserts and tropical islands.”

Approximately 17 species of bats occur in Siskiyou County. Bats have probably inhabited Barnum Cave for centuries, but were first recorded by homesteaders when this system of underground lava tubes was discovered in the late 1860s.

Four people in a cave entrance.

Barnum Cave is one of the many lava tube formations that lie just under the pine-juniper covered landscape in rural Siskiyou County. Each cave has unique features such as large chambers, small grottos and this upper level alcove that reflect the geologic timeline of the area. Credit: Jennifer Jones/USFWS

Named after one of those settlers, Barnum Cave was formed as the result of an eruption of nearby Mt. Shasta nearly 200,000 years ago. Liquefied molten lava flowed down from Shasta in channels, remaining very hot as the surrounding areas cooled. These channels became deep enough to crust over, forming an insulating tube that kept the lava molten and flowing inside. As the flow slowed then stopped, the lava cooled and contracted, leaving the hollow tube formation that became the cave.

A group of people walking into a cave with graffiti on the walls.

Hard-hatted and headlighted visitors have the opportunity to visit Barnum Cave each Fall on a free guided tour led by experts from the Service, Klamath National Forest and the local cave protection society. Because of increased vandalism and threats to cave and bat health, the U.S. Forest Service installed a heavy, locked iron gate to prevent human access when bats are present in the cave. Credit: Jennifer Jones/USFWS

Caves provide habitat for many bat species like the Townsends big-eared bats. Both caves and bats are very sensitive to disturbance. Some local caves have suffered permanent damage through vandalism, as evidenced in Barnum Cave by spray painted walls, broken glass and trash littering the sandy cave floor. As a result, the Klamath National Forest installed a heavy iron gate to prevent human access but allows the colony of nearly two hundred Townsend’s bats to come and go as they arrive for winter hibernation.

“By studying and monitoring these creatures of the night and properly managing the caves they use, bats are better able to fulfill their ecological roles, promote biodiversity and support the health of many ecosystems,” said Jones.

For more information on Bat Week and how you can help conserve our bat populations, visit: batweek.org

 

 

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Susan Sawyer

About the writer...

Susan Sawyer is the Klamath Basin public affairs officer, covering the Klamath Basin National Wildlife Refuge Complex, Klamath Falls and Yreka Fish and Wildlife Offices. She was raised in the California desert gaining a deep appreciation of the outdoors on family vacations to the Pacific coast,Sierras and Redwood forests.

She has worked in Arizona, Nevada, Montana, Idaho and now Oregon, where she spends her free time landscaping for wildlife, continuing to learn from and about nature and spoiling her animals.

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