The number of caves surveyed certainly affects the total count, and varies in any particular year depending on staff availability. Previous years’ survey totals from a similar number of caves ranged from 1,250-1,450 bats. It appears that Townsend’s big-eared bat populations within Lava Beds National Monument continue to be stable and may even be increasing. This is great news, as this species is in decline in elsewhere due to loss of habitat and increased human disturbance. It is also important since healthy bat populations keep insect populations at bay reducing risk to crops and nuisance to humans.
No sign of white-nose syndrome was detected in Lava Beds this year. This fungal disease is killing millions of bats in the Eastern United States and Canada, and continues to spread west. Lava Beds thanks all visitors for participating in the mandatory white-nose syndrome screening process before entering any caves to help reduce the spread of this deadly disease.
Townsend’s big-eared bats hibernate both alone and in clusters, and use their ears for thermoregulation to keep their bodies at the right temperature; some tuck their ears underneath their wings to stay warm, others extend their ears to cool off. The biggest cluster seen this year contained 30 bats.
Surveyors noticed that the bats seem to be congregating into the deeper, colder caves this year. There may be a connection between this behavior and the warm winter weather. One of the cold, deep caves that usually contains 50-100 bats had more than 400 bats during 2015 surveys! Park staff hope to look more closely at the data and better understand the environmental drivers behind hibernating bat behavior.
Trained and qualified staff members from Lava Beds National Monument and partner groups use a stratified random sampling protocol to survey both caves with known winter bat populations and caves that have never been searched during the winter season. This allows for adequate population monitoring as well as the discovery of new bat hibernacula. In the past five years, three new hibernacula averaging more than 30 bats were discovered using this survey method. With over 700 caves, it could be many years before all caves are searched during the winter season; the possibilities abound for finding more hibernating bats.
Lava Beds National Monument, established in 1925, is a land of turmoil, both geologic and historic. Over the last half-million years, volcanic eruptions have created a rugged landscape dotted with diverse volcanic features. Lava tube caves, Native American sites, historic battlefields and a high desert wilderness experience await you!
For more information about visiting Lava Beds National Monument, call 530-667-8113, email firstname.lastname@example.org, or go to www.nps.gov/labe. Also, visit the park’s Facebook and Twitter pages.