California Department of Fish and Wildlife (CDFW) is protecting California’s bat populations by addressing the threat of a deadly disease known as White-nose Syndrome (WNS) with support from the State Wildlife Grant (SWG) program.
WNS is a fungal disease that grows on bats during winter hibernation and can result in a white fuzzy appearance on their muzzle, ears and wings. The disease causes bats to arouse more than usual during hibernation and consequently burn up fat reserves needed to sustain them through winter. They can ultimately end up starving to death.
More than six million bats have died from WNS, and the disease can kill 80 to 90 percent of bats in a colony during hibernation. In some bat species, the mortality rate for WNS can approach 100 percent.
The WNS Response Project focuses on disease surveillance and population monitoring, which is no small feat as these small nocturnal creatures are difficult to find and even more difficult to study. Over the past five years, CDFW has sampled over 1,000 bats at 19 sites statewide to look for the fungus and symptoms of disease. Although they have yet to find bats showing signs of WNS, results of this project show the causative fungus is present across the state, indicating California’s hibernating bat populations could soon be at risk.
Partnership is essential to this SWG funded project, and the U.S. Fish and Wildlife Service National WNS Response Team provides critical leadership and support to CDFW for this work.
California has amazing bat biodiversity, and these tiny flying mammals consume millions of insects each night. Protecting bats is important to the quality of our lives and the quality of our nature.
Quick stats:
- 241 bats were captured and swabbed
- CDFW biologists added more than 150 records to the Report a Colony and Report a Dead/Dying Bat databases
- CDFW biologists added 1,290 records to the Bat Fest database during the 2025 event
- In 2025, 278 bat carcasses were distributed to museums and researchers
SWAP Species of Greatest Conservation Need: Fringed Myotis (Myotis thysanodes), Long-eared Myotis (Myotis evotis), Long-legged Myotis (Myotis volans), Townsend’s Big-eared Bat (Corynorhinus townsendii)
Nestled 7,000 feet above the San Bernadino Valley towering pines, meadows, and marshes make up Bluff Lake Reserve. Home to numerous sensitive plant and wildlife species, it is here that the California Department of Fish and Wildlife (CDFW) is focusing conservation efforts. A team from the Inland Deserts Region, with State Wildlife Grant (SWG) funding, is heading a project to implement priority conservation actions for eastern California fishes. One such priority is to conserve Unarmored Threespine Stickleback and support recovery efforts by establishing a new population at Bluff Lake Reserve. Unarmored Threespine Stickleback (Gasterosteus aculeatus williamsoni) (UTS) are a unique subpopulation of stickleback in Southern California.
Unarmored Threespine Stickleback were discovered in San Bernardino County at Shay Creek in 1981. They have suffered significant range reduction due to human development, and the Shay Creek stickleback are confined to isolated ponds that are vulnerable to extinction and loss of genetic diversity.
Bluff Lake Reserve is a property owned and conserved by The Wildlands Conservancy (TWC) that includes 20 acres of lake habitat. In 2023, 200 fish were successfully translocated and released at Bluff Lake Reserve through CDFW and US Fish and Wildlife permitting. The 2024 monitoring surveys showed successful survival of the translocated fish. In 2025, monitoring surveys confirmed successful reproduction with the capture of young-of-year fish.
The long-term goal at Bluff Lake is to establish a larger, more stable population that can preserve existing genetic diversity and be used as a source population in future recovery efforts. Early success signs indicate that this population has a great chance for survival thanks to the hard-working CDFW Inland Desert team!
- 2 years of successful overwinter survival and reproduction
- 200 fish were released into Bluff Lake in 2023
- The San Diego Zoo Wildlife Alliance is heading release and recovery efforts for R.muscosa at Bluff Lake
SWAP Species of Greatest Conservation Need: Mountain Yellow-legged Frog (R.muscosa), Unarmored Threespine Stickleback (Gasterosteus aculeatus williamsoni)
Snake fungal disease (SFD), caused by the fungus Ophidiomyces ophidiicola (Oo), has emerged as a major challenge for snake conservation across California. SFD was first detected in California in 2019. In 2020, CDFW initiated a five-year study investigating the extent of Oo and SFD across California’s snake populations.
The purpose of this project was to determine 1) how widespread Oo is in California and 2) the degree to which it results in SFD and posing a serious risk to native snakes. To maximize coverage and awareness, CDFW established collaborations with dozens of individuals and organizations involved in snake research and care. The project also included educating the public about SFD and the important role snakes play in a healthy ecosystem through a SFD page. Project results will improve our understanding of SFD’s immediate and potential future risk to California snake populations and inform conservation management decisions.
California is home to 46 native snake species, including 13 species or subspecies listed as SWAP Species of Greatest Conservation Need (SGCN). Many California snake species are already imperiled by habitat loss, degradation, and fragmentation; their populations are often small, isolated, and lacking genetic diversity and thus are especially vulnerable to emerging infectious diseases.
The results of SFD surveillance, public education, and new collaborations are expected to improve CDFW’s ability to assess SFD risk and prioritize areas and species for future surveillance.
Quick Stats:
- From November 22, 2020, to April 29, 2025, 656 snakes from 37 counties were examined for signs of SFD
- Swabs from 628 snakes and 3 shed skins were submitted for testing, representing 32 species or subspecies: 30 native and 2 non-native species
- Of the 628 snakes tested, Oo was detected on 25, including 11 native and 1 non-native species
SWAP Species of Greatest Conservation Need: Alameda Striped Racer (Masticophis lateralis euryxanthus), Coast Patch-nosed Snake (Salvadora hexalepis virgultea), Giant Gartersnake (Thamnophis gigas), Red Diamond Rattlesnake (Crotalus ruber), San Joaquin Coachwhip (Masticophis flagellum ruddocki), San Francisco Gartersnake (T. sirtalis tetrataenia), Two-striped Gartersnakes (T. hammondii)
This project continues long-term monitoring of special concern, threatened, and endangered amphibians, with focus on Sierra Nevada Yellow-legged Frogs (Rana sierrae; SNYLF) by the CDFW High Mountain Lakes (HML) project. This monitoring work is critical for maintaining accurate information on the status and trends of amphibian populations in alpine aquatic ecosystems of the northern Sierra Nevada. This crucial population data informs aquatic ecosystem management decisions, including actions that benefit native species (e.g., translocations, reintroductions, captive-rearing, and targeted non-native fish removal).
An important component of this work involves capture-mark-recapture (CMR) surveys at 10 different SNYLF populations. During CMR surveys, biologists capture adult frogs, insert a tiny chip under the frog’s skin called a Passive Integrated Transponder (PIT) tag, and collect morphological and location data for each captured frog. By tagging each newly captured adult frog, and looking for previously-tagged frogs, biologists can better estimate the true frog population size. As part of this State Wildlife Grant (SWG), CDFW staff initially determined that a few of the smaller SNYLF populations where CMR is being conducted contain more adult frogs than initially suggested by traditional visual encounter surveys (VES). This work has provided conclusive data that more accurately reflects the population size in these locations.
Additionally, this SWG project allowed for the continued monitoring of a SNYLF population in Desolation Wilderness that CDFW and Eldorado National Forest staff established via direct translocation of adult frogs from a nearby robust population. The translocation project began in 2018, and the frog population has grown since. There’s evidence of annual breeding and recruitment of new adult frogs into the population. These initial results are highly encouraging and provide hope for the persistence of these native frog populations.
Quick Stats:
- Monitoring sites located between approximately 4,500' and 9,000’
- Public lands (mainly USDA Forest Service lands) in Plumas, Sierra, Nevada, Placer, El Dorado, Alpine, and Amador Counties
- 51 different SNYLF population sites monitored during the grant period
SWAP Species of Greatest Conservation Need: Sierra Nevada Yellow-legged Frog (Rana sierrae)