Bat Monitoring

Assessing the health of bat populations across Marin.

SEPTEMBER 20, 2020

Mist netting and telemetry research work was cancelled in 2020 due to the COVID-19 pandemic. Acoustic monitoring continued, and scientists are reviewing the data.

AUGUST 6, 2019

Scientists and Parks staff were out at night in Cascade Canyon Preserve on August 5 and 6, 2019, setting up and monitoring bat mist nets. The portable nets were placed near the creek, allowing scientists to capture, examine, and tag some of the bats with radio transmitters. The process is designed to minimize stress and does not cause any injury to the animals. All bats are set free after being examined. Because white nose syndrome has been detected in another part of California, the scientists are especially looking for any signs of this disease, which threatens bat populations across the country.


The Peak Health Mt. Tam report issued by One Tam partners and Bay Area scientists identified a need to study Marin's bats. Seven of the thirteen types of bats residing in Marin may be special status species, yet little is known about them. So in 2016, One Tam, including Marin County Parks, joined with the U.S. Geological Survey to implement a three-year county-wide bat monitoring study.  

The project uses acoustic monitoring, roost surveys, and other techniques. Information collected by this project will determine the health of the County's bat populations, provide insights into bat behavior, inform wildlife conservation, and help scientists watch for white-nose syndrome, a deadly fungal disease that has not yet spread to this area. Repeating the survey in coming years will illuminate status and trends over time, and contribute to nationwide data about bats being collected by the North American Bat Monitoring program.