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Meghan Walla-Murphy stooped to examine a twisted pile of dried poop, obscured by golden grass on an arid ridge in eastern Napa County. It may have belonged to one of the feral pigs that run rampant in the area. Or it may have been evidence of black bears, whose presence in Wine Country appears to be on the rise.

Walla-Murphy picked it up for a closer look.

No undigested identifiers, she said. Probably pig. She set it down and kept hiking.

Walla-Murphy, 46, is an ecological consultant and wildlife tracker who lives in western Sonoma County. Two years ago, she started the North Bay Bear Collaborative, an effort to bring together state wildlife experts, land managers, property owners, nonprofits, tribes and researchers for discussions about cultivating a bear culture in California.

On a recent survey near Atlas Peak in Napa County, Walla-Murphy and a pair of volunteers found 13 signs of bear scat and claw marks on the trunk of an oak.

Volunteer Alan Studley holds what appears to be a charred deer skull found in the slopes of Foss Valley.

The bears are here in the North Bay now, Walla-Murphy said. So, how do we figure out how to live with them?

Incidents involving black bears are escalating in the mountainous areas of Napa, Sonoma and Marin counties, and state wildlife biologists want to know why. Nuisance reports have jumped from an average of about 67 per year from 2010 to 2016 to more than 200 last year and upward of 200 so far this year, according to the California Department of Fish and Wildlife.

Sightings reported to the department have also climbed significantly in the past decade. One of the creatures was even spotted two years ago sauntering through downtown Napa highly unusual behavior.

A running theory is that the rise signals the southern expansion of a large black bear population in Mendocino and Humboldt counties, which could portend more bear-human encounters to come in the greater Bay Area.

If the bears are getting pushed toward the Bay Area, thats their southern limit. Theres real potential for human-wildlife conflicts, said Stacy Martinelli, a wildlife biologist at Fish and Wildlife. Were trying to understand whats going on, so we can make some management decisions before that happens.

Ecological consultant Meghan Walla-Murphy (left) of Sonoma County leads volunteers on a hunt for bear scat in the hills above Foss Valley in Napa County.

First, they need to know how many bears are roaming around.

In decades past, wildlife managers divined population estimates from the number of unique bear teeth provided by hunters and aerial surveys via helicopter crude, imperfect tactics at best. Estimates from Fish and Wildlife put the state black bear population at 30,000 to 40,000 in 2016, up from 10,000 to 15,000 in 1992. Activity around Lake Tahoe, the unofficial black bear capital of California where the animals live about one per square kilometer, is fairly well documented, but its a mystery most everywhere else.

We really dont know as much as we should know about whats happening with bears in different places around the state, Martinelli said.

In the past two years, Fish and Wildlife has embarked on a study that uses genotyping to identify and sex individual black bears in the North Bay by their DNA. Its a relatively new and much less disruptive method that has helped the state more accurately monitor populations of deer, elk and the Sierra Nevada red fox, which was recently listed as an endangered species.

State biologists hope to eventually track bears movements and plot their home ranges as well, which could help the North Bays rural residents better prepare to coexist with their furry new neighbors. Bears have been known to show up at vineyards this time of year to munch ripe grapes off the vine and suck down water from irrigation ponds.

This approach hinges, in part, on the expertise of Walla-Murphy and participation from the bear collaboratives volunteers: The biologists need DNA samples, and the best way to get them is by finding bear excrement. Another way to gather DNA is by setting out hair snares in bear territory designed to snag fur from the animals. But that involves the labor-intensive process of lugging bales of barbwire into remote areas.

Meghan Walla-Murphy hikes into Foss Valley in Napa County during a recent scat survey.

For the past year, Walla-Murphy has orchestrated volunteer surveys in Sonoma, Napa and Marin, and collected hundreds of scat specimens. The samples are processed at UC Davis and logged into a growing database of individuals with identifiers such as Sonoma Female 1 as well as their locations. The more samples Walla-Murphy and her revolving group of volunteers collect, the clearer the picture of bear activity becomes.

With a robust flow of these data points, we can study reproductions, survival, their space use and if theyre concentrating, say, near places where people are leaving their trash out, said Ben Sacks, a UC Davis professor of mammalian genetics who is handling the DNA analysis. There is tremendous potential for these noninvasive genetic methods and a lot of untapped applications.

A deeper dive into the scat specimens could illuminate the bears diets and show whether a given female is pregnant, Sacks said. But thats beyond the scope of the current study. For now, the goal is to get an accurate count and a snapshot of where theyre ranging.

Several factors could be pushing more black bears south toward the Bay Area: drought, food shortages, wildfires or just steady growth of a healthy population.

Usually its not one reason, its multiple reasons, Martinelli said.

Back on the scat hunt in Napa, Walla-Murphy led two volunteers across a ridgeline above Foss Valley, a narrow avenue largely given over to grape-growing, which partially burned in the Glass Fire last year. Amid the blackened landscape, new plant life was emerging: Wildflowers blossomed, and bright, leafy tufts of oak resprouted from charred root crowns.

Walla-Murphy has surveyed this area for years and noticed that the fire didnt chase away the bears for long, like one might have assumed. The animals were present before the fire and returned almost immediately afterward.

Wildlife tracker Meghan Walla-Murphy (second from right) and two volunteers look across vineyards in Napa Countys Foss Valley. The North Bays black bear population is growing.

The fires are often creating more food forage-ability for bears, Walla-Murphy said. We see deer and foxes and bobcats come back right away as well. The animals know how to live with fire.

Within that simple observation is an insight Walla-Murphy hopes will steer the direction of bear management in California: A more natural landscape supports more natural animal behavior, which makes living with wildlife easier for humans.

If we can really begin to steward and tend our landscapes better so that theres more diversity and theyre regenerative and they have more forage for wildlife, that ideally will keep the bears in their natural habitat rather than pushing them into cities for food, she said.

Gregory Thomas is The San Francisco Chronicles editor of lifestyle a outdoors. Email: gthomas@sfchronicle.com Twitter: @GregRThomas

Original post:
Bear incidents are rising in the North Bay. Biologists sent in a wildlife tracker to find out why - San Francisco Chronicle

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