Annual public tour provides up-front experience
by Susan Sawyer, Klamath Basin Public Affairs Officer, US Fish & Wildlife
SISKIYOU COUNTY, Calif. - 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.
“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.”
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.
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.
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