Featured Scientist

Alisa Ellsworth holds a newly-collared bobcat for the Eastern Sierra Bobcat Project.


Alisa Ellsworth and crew working on Fish Slough Ecological Reserve restoration project.

CDFW Senior Environmental Scientist Alisa Ellsworth supervises the Inland Desert Region’s Northern Lands Program. Based out of the Bishop office, Alisa oversees 10 employees who perform a wide variety of activities including land acquisition planning, coordinating mitigation for incidental take, and managing over 120,000 acres of state ecological reserves and wildlife areas in Inyo, Mono and San Bernardino counties.

A Central Valley native, Alisa grew up in Visalia. She attended both undergraduate and graduate school at Fresno State, where she completed a bachelor’s degree in botany in 1993 and a master’s degree in biology in 1995. Her thesis focused on vernal pool ecology in Madera County.

What inspired you to become a biologist?

My interest in science first started in high school when I had to do an insect and plant collection for my biology class. I really enjoyed learning how to identify things in nature. When I started college, I was naturally drawn to biology courses and my path was set. I met a group of people that liked to go out botanizing and birding on the weekends and a whole new world opened up for me.

My first wildlife job was in 1992 with Pacific Southwest Research Station, estimating the density of spotted owls in Sequoia National Park. This is where I learned how to hike at night using a compass and topographic map, as there weren’t GPS units back in those days. The work also involved gathering vital rate data (reproduction and mortality) as well as characterizing diets from regurgitated pellets. In 1993, I spent an amazing summer working for the US Forest Service. I hiked all over the Sierra National Forest, mapping vegetation types and looking for rare plants.

How did you come to work for CDFW?

I worked as a scientific aide for the Habitat Conservation group in the Central Region for a year and a half when I was in college. After I graduated, I began working as a private consultant until 1996 conducting rare plant surveys, wetland delineations and revegetation projects. Around that time, I caught the travel bug and applied for a research assistant position focused on field studies of the guanaco, a South American wild camelid related to the llama. This took me to Torres Del Paine National Park in the Patagonia region of southern Chile, where I worked on guanaco reproductive strategies, spacing strategies and movement. We radio collared young guanacos (called chulengos) and monitored for survival and cause-specific mortality. This involved watching a mother give birth to her baby and then soon after running in and grabbing the baby and quickly putting a radio collar on it. Most of the mothers were pretty mild mannered, but one tried stomping on us and spit all over us, which was quite smelly!

Afterward, I joined the Peace Corps and stayed in Ecuador until 1999, working on environmental education projects in schools. When I returned to the United States, I worked briefly as a consultant again, and then took an associate biologist position with Caltrans in Fresno. When a position opened up in CDFW’s Bishop office, in the streambed alteration agreement program, I jumped at it. I was hired in 2001 and have never wanted to leave Bishop since.

Over my career with CDFW, I have managed the X9B and X9C deer zones, the Owens Valley tule elk zones and the White Mountain bighorn sheep hunt zone. I have collected and analyzed wildlife population data for upland game birds, mule deer, tule elk and Nelson bighorn sheep. I’ve provided harvest recommendations and direction for population management of those game animals. Since 2008, I’ve been with the Lands program, working on acquisition projects, writing grants and working with the Wildlife Conservation Board and other non-governmental organizations on projects of shared interest.

We sometimes say that the Eastern Sierra is “the most beautiful part of California you’ve never seen.” What is unique about this ecosphere?

The Eastern Sierra is comprised of mostly public land with very little development compared to many other areas around California. This allows for intact wildlife populations to exist in vast expanses of native habitat. For example, the federally endangered Sierra Nevada bighorn sheep can be found in the high alpine environment in the summer months. They then move downslope in the winter to take advantage of available food not buried under snow. More than 600 bighorn in 13 occupied herd units can now be found in the Sierras, compared to 1995 when there were only 105 left after being devastated from diseases transmitted from competing domestic livestock in the high alpine meadows.

The sheer beauty of the tall mountains and the abundance of wildlife make it a truly special place. I enjoy hearing the tule elk bugling in the fall evenings near the Owens River. If you really want a treat, you can wake up before the sun rises to go observe the greater sage grouse congregate on their leks (meadows or barren areas with little cover) during the spring breeding season. The males put on quite a display in hopes of attracting a female by puffing out their chest, inflating air sacs and making unique sounds that I equate to drops of water.

What kinds of projects are conducted on the reserves and wildlife areas you manage?

Our activities are quite diverse, including managing water rights and grazing, controlling invasive species and performing various wildlife surveys. I serve as the lead for the Eastern Sierra bobcat study, which was initiated in 2014-2015 as part of a three-year project to assess current populations in Inyo and Mono counties. Specific data collected during the study include bobcat population size, density and age structure, as well as home range size, habitat selection, prey base and reproduction.

I also am also the lead for the low-elevation mesocarnivore survey project. This involves the use of remote cameras to capture detailed images of wildlife species such as bobcat, coyote and gray fox. The surveys help us estimate the percent of the study area that a species of interest occurs by placing one camera within a 10.4 Km cell and surveying 100 cells over multiple weeks. The data collected provides occupancy of the species surveyed. Capture-mark-recapture surveys can be done using this method with species such as bobcats that can be identified because of their unique coat patterns.

Inyo and Mono counties have been divided into eight study areas using geographical boundaries that the mesocarnivore surveys will be rotated through. Initially, these surveys will provide occupancy and abundance of individual species within each study area. Over time, data collected from the surveys can be useful to identify population trends.

What has been the most satisfying part of your CDFW career?

I really enjoy working with outstanding people who are focused on managing and conserving the state’s most important places and wildlife. I’m particularly proud of the conservation work that’s been conducted for the benefit of the Round Valley deer herd. We purchased several important properties within its winter range in Rovana and Swall Meadows, with the goal of protecting an intact migration corridor for them to move up and down in elevation to and from their winter and summer ranges.

What projects would you undertake if you had unlimited money and resources?

I am passionate about conserving natural areas for the perpetuation of healthy ecosystems and the wildlife populations they support. California is an incredibly biologically diverse state and these places are truly unique. By protecting them, we will allow them to be enjoyed generations to come. My most recent focus has been working to conserve the greater sage grouse through land acquisition and conservation easements. Funding all of the proposed actions in the Bi-State Action Plan for Greater sage grouse would be a dream come true.

CDFW photos.
Top photo: Alisa Ellsworth works a Sierra Nevada bighorn sheep capture.

Tim working a deer capture in Round Valley. The deer was captured with a net gun, blindfolded, and hobbled for helicopter transport to base camp or a central processing station.


Tim radio-collared and took samples from this anesthetized black bear during the 2016 Eastern Sierra Black Bear Study.

Tim Taylor is an environmental scientist for CDFW’s Inland Desert Region, which includes Imperial, Inyo, Mono, Riverside and San Bernardino counties. He has spent his entire 17-year CDFW career in a single area of study – the Eastern Sierra – and he is only the third Mono County unit biologist in department history.

Like many other CDFW scientists, Tim earned his Bachelor of Science in wildlife management at Humboldt State. The Southern California native did myriad odd jobs to get through college, including working on a ski lift, putting up drywall and even thinning trees and fighting fires. After college, he worked as an independent biologist throughout California, Oregon and Nevada, conducting wildlife assessment surveys for a wide range of threatened and endangered species including desert tortoise, red-legged frog, spotted owl and Sierra Nevada red fox.

Today, Tim’s primary job duties include monitoring diverse wildlife species – including sage grouse, deer, pronghorn and bears – in a part of the state most Californians never have the opportunity to experience.

Who or what inspired you to pursue a career in wildlife biology?

When I was a kid growing up in the June Lake area of the eastern Sierra, I always knew I wanted to be a wildlife biologist. I had the good fortune of getting to know the very first CDFW wildlife biologist for the Mono unit, Andy Anderson, and he took me into the field with him whenever possible. I got to participate in some amazing wildlife work, like trapping and relocating nuisance black bears (when we used to do that!), rearing Canada goose goslings, counting strutting sage-grouse and helping at deer hunter check stations. This work provided me with an early appreciation and knowledge of eastern Sierra wildlife and their habitats, and from that time on, the Mono unit biologist position became my dream job.

After Andy retired, I became good friends with his successor, Ron Thomas. He was also a great mentor. I started working for CDFW in the Sierra Nevada bighorn sheep program with the hope of eventually transferring to the Mono unit position. Fortunately, after Ron retired, I was in the right place at the right time.

What are your current responsibilities?

Working as a unit wildlife biologist requires being a generalist with the knowledge and understanding of all wildlife that inhabit my work area. During any given day I can deal with a number of different wildlife species issues like sage-grouse habitat conservation, mule deer and pronghorn research, nuisance black bear complaints and talking with deer hunters about the best place to find a buck. My duties include wildlife resource assessment, habitat enhancement planning and implementation, hunting management, nuisance wildlife response and environmental review. I am currently involved with a number of different wildlife research projects, including a sage-grouse translocation effort to rescue a small, isolated sub-population near the Mono basin and a GPS collaring study of black bears to determine home range distribution and habitat use.

I also occasionally provide advice on how to reduce human-bear conflicts at the Mountain Warfare Training Center, a US Marine Corps installation in Mono County. I review environmental documents that relate to their training area, and work with new recruits on how to identify animals, as part of their survival training.

Which species do you work with most frequently?

Mule deer are the most conspicuous and widespread large mammal in the eastern Sierra. Mono county supports five large migratory herds. I manage 2 mule deer hunt zones, X12 and X9a. Hunt zone X12 comprises three herds that occupy northern Mono County. These are interstate herds that are jointly managed for hunting purposes by CDFW and the Nevada Department of Wildlife. Zone X9a comprises two herds that occupy southern and central Mono County. Those are managed solely by CDFW. Along with other CDFW biologists, I conduct population surveys and collect data on vital rates and nutritional condition as part of an integrated population monitoring approach for assessing the status of local deer herds.

Mono County also supports a large population of greater sage-grouse, which is part of the Bi-state Distinct Population Segment (DPS) of greater sage-grouse. The Bi-state DPS, which is genetically distinct from other sage-grouse across the range, occupies sagebrush habitat in Inyo and Mono counties in California and Douglas, Mineral, Lyon and Esmeralda counties in Nevada. Sage-grouse is a sagebrush obligate species, meaning it relies on sagebrush for its survival. They are also an umbrella species, used in making conservation related decisions that affect the sagebrush ecosystem. Our efforts to conserve the sage-grouse indirectly protects other sagebrush obligate species, such as pygmy rabbit and Brewer’s sparrow, that inhabit the sagebrush ecosystem.

Then there’s the eastern Sierra black bear. Their population has increased dramatically over the last 10 years, and therefore has created numerous management challenges. In most of the rural east side towns there is no regular garbage pickup, so people store their trash and take it to a landfill. This creates a situation where bears have open access to garbage that is not properly secured in a building or bear-proof container. Once a bear has become food-conditioned, it’s pretty much over. It will start breaking into homes and cabins next.

What project or accomplishment are you most proud of?

In 2007, CDFW acquired 1,160 acres of critical greater sage-grouse habitat in northern Mono County, which included two strutting grounds, brood rearing meadows and winter habitat. Approximately 900 of the 1,160 acres was proposed to be subdivided into 40 acre parcels, which included the only two remaining leks for this sub-population of sage-grouse, as well as some critical mule deer migration and summer range habitat. CDFW acted in a timely manner in acquiring the property, and in doing so, prevented the loss of this critical sage-grouse habitat.

Without the acquisition and eventual conversion of the property into a State Wildlife Area, these leks would have been destroyed resulting in the extirpation of this sage-grouse sub-population.

The acquisition was funded by the Wildlife Conservation Board, and was especially important because it was one of the many conservation actions that helped to prevent the federal listing of the Bi-state greater sage-grouse.

What project would you most like to do, given unlimited time or resources?

I would implement several much needed wildlife crossing projects that would include a combination of underpasses, overpasses and fencing to allow deer, bears and other wildlife safe passage across highway 395 in Mono County.

What do you love most about your job?

The fact that I have the flexibility to work with so many different wildlife species on so many different projects.

What advice would you have for a young scientist wanting to do what you do?

Try to become as diversified as possible with respect to your knowledge of wildlife throughout the state. Working as a unit biologist requires multiple species management so become a naturalist and develop a broad understanding of the species that inhabit your work area.

Photos courtesy of Tim Taylor
Top photo: Tim working on a Round Valley deer herd capture team