Science Spotlight

CDFW Photo: The Western Section Wildlife Society president Randi McCormick and Atlas staff (Sardinas, Richardson and Winkler) receiving the Conservationist of the Year award at the 2023 conference.

CDFW Photo: Yellow-faced bumble bee.


CDFW Photo: Community science volunteer photographing a chilled bee at an Atlas field training.

The California Bumble Bee Atlas (Atlas), a collaborative community science project developed to track and conserve the state’s native bumble bee species, has been awarded Conservationist of the Year by the Western Section Wildlife Society.

The award, given to a person or group that has made an outstanding contribution to wildlife conservation in California, Nevada, Hawaii or Guam, was presented by the Western Section at its meeting earlier this year.

“It’s an honor for the California Bumble Bee Atlas to be recognized for its contribution to conservation and a testament to the power of community science in addressing critical issues like pollinator decline,” said Hillary Sardiñas, statewide pollinator coordinator for the California Department of Fish and Wildlife (CDFW), and one of the scientists behind the Atlas.

CDFW was awarded funds through the competitive State Wildlife Grant Program to support the Atlas, which is led by CDFW in partnership with The Xerces Society for Invertebrate Conservation (Xerces). CDFW and Xerces staff developed a website to compile resources for volunteers, recruited and trained community scientists from around the state and are using data gathered to help identify priorities for bumble bee conservation in California.

Bumble bees are charismatic and easily recognizable pollinators thanks to their large size and distinctive striped patterns. Bumble bees are predominantly black and yellow but can have red, orange or white coloration. They play an important role in keeping the environment healthy by pollinating flowers in natural areas and contributing to successful harvests on farms.

Recent declines of pollinator populations have drawn attention to their importance in providing ecosystem services, including to over 30% of agricultural crops. In California, eight of the state’s 25 bumble bee species are classified as endangered or vulnerable by the International Union for Conservation of Nature (IUCN).

“Many bumble bee species are in a precarious position due to interacting threats, including habitat loss, climate change and disease spread. The California Bumble Bee Atlas can help track population trends to help identify species and locations for targeted conservation actions,” said Leif Richardson, Atlas lead for Xerces.

To improve understanding of trends in bumble bee populations, Atlas staff train volunteers to collect data without harming bumble bees. Volunteers net bumble bees then chill them to take close-up photos that enable identification. The bumble bees then slowly warm up and fly away. All data and photos are uploaded to the website Bumble Bee Watch, where species are identified by expert taxonomists.

Over 2,000 people have registered for the Atlas as volunteers. These volunteers have conducted thousands of surveys across the state and are the driving force behind the Atlas. Between 2022 and 2023, volunteers and project staff recorded 10,009 bumble bee observations.

“The Atlas wouldn’t be possible without the support of community science volunteers, which have included a number of CDFW staff from around the state. We’re still looking for new volunteers to survey bumble bees and help contribute to this important project,” added Dylan Winkler, CDFW scientific aid for the Atlas.

Going forward, the Atlas will have a new objective: to identify long-term monitoring sites that volunteers visit multiple times a year. This data will provide short- and long-term trends in high-priority locations that support or historically contained California’s bumble bees of greatest conservation need. All data collected from the project will help with the development of a management plan for bumble bees in California, which CDFW and Xerces hope will continue to catalyze conservation of these charismatic and important species throughout the state.

For more information or to get involved, visit the Atlas’ website at cabumblebeeatlas.org.

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Media Contact:
Amanda McDermott, CDFW Communications, (916) 738-9641

The National Oceanic and Atmospheric Administration (NOAA) has recognized a CDFW senior environmental scientist for his role in the historic effort to return endangered winter-run Chinook salmon to the McCloud River for the first time since construction of the Shasta Dam in the 1940s.

Matt Johnson, CDFW’s fisheries supervisor for the winter-run Chinook salmon reintroduction pilot project, was given NOAA’s Partner in the Spotlight Award on Jan. 25, 2024. Johnson oversaw many of the project’s critical components including remote site incubation, trapping of juvenile winter-run and coordinating with project partners including the Winnemem Wintu Tribe.

“It was a surprise and an honor. I threw myself 100 percent into the project so I’m appreciative of the recognition. The project turned into a fascinating and unique opportunity to do something new and historic. It was all unexpected,” Johnson said.

The project launched in summer 2022 in response to drought conditions affecting Shasta reservoir and the lower Sacramento River downstream of Shasta reservoir. Multiple years of severe drought drastically reduced cold-water storage that endangered Chinook needed to live and spawn. CDFW, NOAA, Winnemem Wintu Tribe and the U.S. Fish and Wildlife Service (USFWS) partnered to move winter-run eggs upstream to the McCloud. The river offered favorable habitat including summer cold water conditions required for spawning but was inaccessible to fish because of the dam.

Partners initially relocated about 20,000 fertilized winter-run Chinook salmon eggs from USFWS’ Livingston Stone National Fish Hatchery near Redding. The eggs were transported 80 plus miles to the banks of the McCloud where the species historically spawned prior to construction of the Shasta Dam. The eggs were then placed in specialized incubators. In early August, another 20,000 eggs were transferred to the incubators.

The eggs were released into the river as fry, which were then collected in rotary screw traps and fyke nets, which are devices used that safely capture small salmon. Once collected, the fry were transported downstream of Shasta Dam and successfully released into the Sacramento River so the fry could migrate to the Pacific Ocean.

“Matt and his CDFW colleagues truly went above and beyond to return winter-run Chinook salmon to their historical home in the McCloud River for the first time in over 80 years. It’s clear that this was not just a job for him – he cares deeply about these species, this river, and this ecosystem and he put his heart into bringing them back,” said Brian Ellrott, NOAA’s Central Valley Salmonid Recovery Coordinator.

“Matt is dedicated to ensuring that this historic winter-run salmon pilot project succeeds. He recognized the insight and history the Winnemem Wintu Tribe provided and embraced their contribution to the reintroduction of the McCloud winter-run salmon,” said CDFW Director Charlton H. Bonham. “Matt is humble and passionate about his profession and we’re proud that he is part of our CDFW family.”

Johnson added: “I couldn’t have done any of this without my team. We were a small but dedicated crew and we were fortunate to have support from management, NOAA, the Winnemem Wintu Tribe, UC Davis and the Mount Shasta Fish Hatchery. Seeing an iconic California species returned to its historic habitat after a nearly 80-year absence was pretty incredible.”

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Media Contact:
Peter Tira, CDFW Communications, (916) 215-3858

Bat surveillance crew

Screening for White-nose Syndrome


Acoustic detector station


Scientist Amanda Kindel with Myotis bat

If California’s hibernating bat species make it through this winter with a full, undisturbed hibernation cycle, there are a few CDFW scientists who may be sleeping soundly as well.

CDFW’s bat conservation team has ramped up its statewide surveying efforts in the past few years. The team is amassing a large amount of data on bat activity. Some of the work is geared toward general species conservation. But most of it has a very intentional focus: staying ahead of White-nose Syndrome (WNS), a disease that has wreaked havoc on East Coast and Midwest bat populations.

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.

In the United States, WNS was first found in 2006 in upstate New York. It likely traveled here from Eurasia. In 2016, hikers in Washington found a sick bat on a trail and took it to a wildlife rehabilitation center for treatment. It tested positive for WNS and died shortly thereafter. Scientists soon found two more bats that tested positive for WNS. The disease continued to spread.

In California, scientists detected low levels of the fungus that causes WNS in 2018 in Plumas County. While they have continued to detect low levels of the fungus since then, they haven’t found the disease. However, WNS surveillance in Texas and elsewhere has revealed a concerning pattern: WNS has taken a foothold in bat populations within two to three years of the fungus being detected. California is home to 25 bat species, and at least nine of them are deep-hibernating bats susceptible to the disease.

“It’s somewhat reassuring that we haven’t seen the disease in California and only low-level detections of the fungus. But it’s also mystifying because we kind of expected to be seeing the disease by now,” said CDFW Wildlife Biologist Dr. Scott Osborn.

The CDFW team is currently in year three of its White-Nose Syndrome Response Project. The team consists of Osborn, Senior Wildlife Veterinarian Dr. Deana Clifford, and Scientific Aids Amelia Tauber, Amanda Kindel and Dylan Winkler. Additionally, volunteers assist with field work.

Over the past two years, the team has sampled for the fungus at 11 sites statewide. CDFW also partners with the National Park Service on bat surveillance. Between the two organizations, surveillance for WNS occurs throughout much of California.

The team is also setting up a network of detector stations for bats. The stations record bat calls on a nightly basis and will help scientists identify activity levels of various bat species. Scientists can then correlate activity level changes with detections of WNS or the fungus that causes it.

“The whole idea is if WNS comes in and starts affecting susceptible species, we should see their level of activity drop off compared to other species that aren’t susceptible to WNS,” said Osborn.

The team currently has eight stations in and around Plumas and Tehama counties, and another four on the north coast. They are scheduled to install four more stations in the northern Sierra this month.

“We’ve got this pretty massive effort to collect data on bat activity. It’s exciting. The data will not only help us detect the impact of WNS if it ever shows up, but it’s also giving us really important information on the timing of activity of various bat species, and bat community composition. It’s possible that in the long run we could use the data to detect impacts from climate change – for example if bats are becoming active earlier in the year due to warming or have to change their activity levels due to heat,” said Osborn.

Since 2009, a national interagency team has been working on WNS response. In the past few years, the team has developed several treatment and management techniques which are starting to be implemented in bat habitats. Outside of California, scientists are testing a vaccine that is typically applied to bats during their active season. The goal of the vaccine is to make bats less susceptible to the fungus when they go back into hibernation. Scientists are also working on a probiotic spray that can be applied to bat roosts during active season. Microbes in the probiotic spray appear to make bats less susceptible to WNS. Another experimental treatment involves shining ultraviolet light into a hibernation site to reduce its fungal load.

Not all of the new treatments are applicable to most California bat populations, which don’t typically congregate in large numbers in hibernation sites. Nevertheless, some of the treatments offer hope for reducing the devastating effects of WNS. Meanwhile, CDFW’s bat conservation team will continue working to stay ahead of the disease.

“It’s important for us to understand what’s going on with WNS so we can implement some of these measures if it is ever detected in California. Bats are beneficial to the ecosystem by helping control pests on agricultural lands and elsewhere. They distribute nutrients to the environment by processing insects. They’re fascinating creatures,” said Osborn.

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Media contact:
Ken Paglia, CDFW Communications

CDFW offers tips for keeping pets and livestock safe

Following several mountain lion sightings in Boulder Creek and forested areas of Santa Cruz County, the California Department of Fish and Wildlife (CDFW) is reminding residents to take precautions to keep pets safe. In addition to recent sightings, there have been several unconfirmed reports of pets taken in the Boulder Creek area which could be attributed to any number of predators including mountain lions, coyotes or bobcats.

CDFW will be hosting a public meeting on mountain lion deterrence on June 17 at 1 p.m. at the Boulder Creek Fire Department. The meeting can also be attended virtually. Check CDFW’s mountain lion web page for the Zoom link and meeting information.

“Mountain lions typically avoid humans, but they can take pets and livestock easily if residents don’t take precautions. Implementing deterrence efforts can be effective,” said Haley Jones, CDFW Human-Wildlife Conflict biologist.

CDFW recommends keeping pets indoors whenever possible to protect them from all predators, including mountain lions. This recommendation applies everywhere in California but especially to residents who live in areas adjacent to wildlife habitat.

For cats that go outside, residents can invest in an outdoor cat enclosure, often called a cat patio or “catio.” Dogs should be kept inside overnight and ideally supervised while outside. Dog owners can invest in lighted collars as a visual deterrent or protective collars designed to lessen the impact of predator bites.

For outdoor animals such as chickens, ducks, goats or other livestock, residents can invest in enclosures and other improvements such as predator proof fencing.

For people who recreate outdoors, CDFW recommends going with a group and avoiding hiking at dusk and dawn. CDFW also recommends carrying a noise deterrent such as a self-defense alarm keychain.

“Even talking loudly when outside can be a deterrent. There’s been research showing mountain lions avoid areas where they can hear people talking. Other predators such as coyotes and bobcats may also avoid approaching when they hear humans,” said Jones.

Here are some additional safety measures that residents can take:

• Remove dense vegetation from around the home to reduce hiding spaces.
• Install outdoor lighting to make it difficult for predators to approach unseen.
• Secure livestock and outdoor pets in sturdy, covered shelters, especially at night.
• Deer-proof your property to avoid attracting a lion's main food source.

“Mountain lions don’t want to be near people, but they sometimes cut through our neighborhoods to get to suitable habitat. They’ll take advantage of an easy meal if they see one, so as pet owners it's on us to make small adjustments,” said Jones.

Residents are encouraged to report mountain lion sightings and encounters to CDFW through its Wildlife Incident Reporting system.

“The reports help us track and keep data current so we can inform communities,” said Jones.

Mountain lions live across much of California including along urban-wildland interfaces where they hunt for deer and other animals. They are ecosystem contributors and a crucial part of maintaining habitat biodiversity. However, it’s typically rare to see a mountain lion because they are elusive creatures. If you do see a mountain lion or mountain lion cub, do not approach it or intervene. Remember that adult mountain lions, when out hunting prey, may leave offspring somewhere safe for up to several days at a time. Questions and concerns can be directed to your regional CDFW office or by submitting a Wildlife Incident Report.

For additional information visit CDFW’s mountain lion web page and CDFW’s Human-Wildlife Conflicts toolkit.

Media contact:
Ken Paglia, CDFW Communications, (916) 825-7120

With less competition from non-native species, native Lahontan cutthroat trout are growing larger in Silver Creek.

Amid the intense, physically demanding native trout restoration work taking place in the fall of 2022 on Silver Creek, Mono County, Nick Buckmaster allowed himself a momentary indulgence.

A senior environmental scientist supervisor with the California Department of Fish and Wildlife (CDFW), Buckmaster paused long enough to imagine himself camped on the banks of Silver Creek within the Humboldt-Toiyabe National Forest, perhaps on vacation, maybe in retirement. It was a warm, summer evening in his mind’s eye, and Buckmaster was casting a dry fly to rising wild and native Lahontan cutthroat trout in the 14- to 16-inch size class.

Such a scenario would have been unthinkable just a couple of years ago. Silver Creek has been closed to fishing of any kind for almost 30 years to protect the remnant population of native trout. Overrun with more aggressive, non-native brook trout despite attempt after attempt to remove them, Silver Creek’s Lahontan cutthroat trout (“LCT” in fisheries parlance) have been clinging to a marginal existence within their home waters.

Today, however, Buckmaster’s dream is closer to reality than it has been in a generation. The Lahontan cutthroat trout recovery work taking place in Silver Creek the last few years represents one of the largest and most ambitious wild and native trout restoration efforts in California history. And nowhere else throughout the Great Basin where Lahontan cutthroat trout were once so abundant is this recovery work happening more quickly, more innovatively and more successfully than in little Silver Creek.

And many eyes are on Silver Creek, a tributary of the West Walker River located about 20 miles northwest of Bridgeport in the hills above the Marine Corps’ Mountain Warfare Training Center. The recovery work there, which will resume in the summer of 2023 as snowmelt allows, is taking place at a moment when federal and state wildlife officials are seeking to accelerate Lahontan cutthroat trout recovery throughout the West. The fish have languished as a listed species under the federal Endangered Species Act for more than 50 years.

Buckmaster and his supervisor, Environmental Program Manager Russell Black from CDFW’s Inland Deserts Region, took on the Silver Creek recovery project in 2020 during the height of the COVID-19 pandemic when social distancing and stay-at-home mandates shut down a lot of other field work. New to the project and passionate about wild trout, the two were either unburdened by decades of past failures at Silver Creek or simply naïve to conventional thinking that Silver Creek and its genetically pure strain of Walker River Basin Lahontan cutthroat trout were a lost cause.

The two supervising fisheries biologists were also on something of a roll having led CDFW’s successful, five-year effort to rescue the federally endangered Owens pupfish, a species so rare it was once declared extinct. That undertaking opened up several square miles of additional pupfish habitat after the removal of non-native, predatory species and helped improve genetic diversity, capturing the imagination of The New York Times in the process.

The same dewatering techniques Buckmaster and Black deployed in the lowlands of the Owens Valley to eliminate non-natives and help pupfish are proving equally effective in the mountains of Mono County to help Lahontan cutthroat trout. Applying those techniques to a small stream environment was a first. For CDFW staff new to the project, training was held last spring at nearby Slinkard Creek (YouTube).

By mid-September, Buckmaster was leading a 10-person crew of fellow fisheries biologists and scientific aids over eight consecutive days of intense field work that involved temporarily lowering flows in portions of Silver Creek (sometimes for a mile or so at a time) to remove the brook trout and relocate the Lahontan cutthroat trout to higher, previously treated reaches upstream that are now brook-trout free. It was Buckmaster’s sixth trip and treatment of Silver Creek of the eight he and his CDFW colleagues would conduct in 2022.

Last year was also a milestone in that CDFW was able to treat all 11 miles of Silver Creek and its tributaries targeted for brook trout removal. The work began at the meadowed, headwaters section and extended 9 miles to rocky, pocket water downstream where a steep waterfall prevents brook trout from moving up into Silver Creek’s higher reaches and best trout habitat.

The goal is not suppression but total removal of the non-native trout within those 11 miles of prime habitat.

“If you leave two brook trout in the system and one happens to be male and the other happens to be female, you’ve lost,” Buckmaster said. “The brook trout will repopulate and take over the creek. And in that case, we might have just as well stayed home and watched football.”

Dewatering Silver Creek begins with installing a temporary sandbag dam. Large, flexible poly pipe not much thicker than a heavy-duty trash bag is attached to the dam, rerouting most of the creek flow more than a mile downstream. Below the dam, the creek is subdivided into quarter-mile sections with barriers installed to block fish movement.

With Silver Creek’s flow significantly reduced and the trout concentrated in the remaining water, electrofishing teams move in, stunning the fish with electrical current and netting those that float toward the surface. The Lahontan cutthroat trout, outnumbered by brook trout 10 to one in Silver Creek’s lower reaches where the September work occurred, are collected and separated from the brook trout. They are measured, recorded and moved upstream of the sandbag dam and released into previously treated sections of the creek. The brook trout are set aside in buckets for later stocking into nearby Kirman Lake for recreational fishing.

Following the initial electrofishing, separate CDFW teams move in with portable pumps to dry up any last remaining pools and puddles that may still be harboring fish. The crews continue to electrofish, move rocks, look under tree roots and probe crevices for fish. A third “clean-up crew” follows behind the pump teams to triple-check the work as water slowly begins to return. The process is repeated over multiple days and over multiple trips.

“No matter how many passes you do with the electrofishing equipment, you keep finding fish until you completely dewater the creek,” Buckmaster said.

While painstaking and physically demanding, dewatering has proven more efficient, less costly and more environmentally friendly than alternative recovery measures used in the past.

CDFW treated Silver Creek with Rotenone in 1994, 1995 and 1996 only to see brook trout return in the early 2000s. Over the past 20 years or so, a variety of government agencies, conservation organizations, fly-fishing clubs and other permitted volunteer groups have also contributed to recovery efforts with periodic brook trout removal. And yet the non-natives persisted.

“Dewatering is an amazing tool,” explained CDFW’s Black. “We’re able to both remove the invasive species and at the same time put that native species right back into the system the same day. That’s having a real positive benefit for LCT while not impacting the creek or the invertebrate community.”

Restoring Silver Creek for Lahontan cutthroat trout has positive ramifications for other native species. As the brook trout population is eliminated, CDFW scientists are encountering more Sierra Nevada yellow-legged frogs. As Silver Creek becomes more hospitable to Lahontan cutthroat trout, it paves the way for the potential reintroduction of other native fish such as speckled dace, mountain whitefish and mountain sucker.

“It’s an all-around win for all native species in what’s a climate-resilient habitat,” Buckmaster said.

Among the end goals, said Black, is to reopen Silver Creek once again to recreational fishing, most likely as part of CDFW’s Heritage and Wild Trout Program, giving anglers a chance to catch wild Lahontan cutthroat trout in their native habitat in a spectacular setting. That prospect may still be a few years away. Black estimates Silver Creek will need two or three additional seasons of dewatering treatments to confirm the complete absence of brook trout. Subsequent monitoring could also be accomplished through eDNA, which can detect brook trout presence simply by testing water samples.

Since 2020, about 15,000 brook trout have been removed from the system, and Lahontan cutthroat trout appear to be thriving in Silver Creek’s upper reaches that are now mostly brook-trout free after multiple dewatering treatments.

“We’re seeing young-of-the year LCT in the headwaters, which we’ve never really seen before, and we’re getting large numbers of adult fish in the system in the 1- to 2-year-old age class,” Black said.

Last fall, some of those adult trout measured 12- to 14-inches in length. It’s the stuff of fly-fishing dreams.

CDFW Photos: Wild trout experts Allison Scott and Gabriel Singer probe for brook trout as a portion of Silver Creek is pumped dry. Signage along Silver Creek proclaims Lahontan cutthroat trout a "California Treasure" and directs anglers to nearby waters that are open to fishing for the native species. Large, flexible poly pipe reroutes most of Silver Creek's water flow around the work zone targeted for brook trout removal. Nick Buckmaster surveys the work taking place at Silver Creek in the fall of 2022.

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Media Contact:
Peter Tira, CDFW Communications, (916) 215-3858