Column: People need to change behaviors to reduce human/bear conflict issues in Lake Tahoe

Not only was 2021 a chaotic year in South Lake Tahoe for a number of reasons, but we also experienced a record number of bear/human conflict issues. I've heard a number of people opine that this was due to the Caldor Fire, but that is not only an over-simplistic view. The fire actually had little effect on the activities of our local "urbanized" black bear population other than giving them free reign in neighborhoods around town, and in some of those areas for up to three weeks, during the Caldor Fire evacuation.

The phenomenon of urbanized black bears is a relatively new thing in the last 15 or so years, not only in SLT, but also in Asheville, NC, Aspen, Colo., Mammoth Calif., and a few other places that black bear populations spend a vast majority of their life living within and closely around urbanized areas, specifically in places that have an urban/wildland interface.

What does the term "urbanized" mean in relation to black bears?

Well, black bears are extremely intelligent omnivorous/opportunistic feeders that can survive on a broad range of calorie sources, and we lazy humans have been more than obliging in providing them with the easiest calorie sources they have ever obtained. Not only have we provided them access to endless calories easily obtained in minutes, as opposed to foraging for natural calorie sources for hours upon hours in their natural wildland environment, we're also providing that calorie source 52 weeks a year! So the lure of easy calories has enticed them in, and their high level of intelligence has helped them to thrive in this urban environment.

It also didn't take them long to figure out that under decks or poorly secured/unsecured crawl spaces make wonderful protected and safe summer day bedding or over-winter denning sites. It's been my experience that once one bear has used one of those spaces for bedding or denning, others will also use it and it becomes what I call a "Bear Bed and Breakfast". We have multiple generations of local black bear sows that only den and give birth in crawl spaces or under-protected decks.

What have been the physiological and behavioral effects of the urbanization of black bears?

Physiologically our local urbanized black bear population tends to be 25-35 percent larger/heavier than their wildland cousins, often giving birth to three cubs as opposed to wildland bears birthing one or maybe two. Due to easy calorie access 52 weeks a year many of our urbanized black bears forego full torpor (the proper term for how black bears over-winter) and actively feed throughout the winter.

Urbanized black bear behavior is a very important factor because a behavior is not only learned, but it is then taught to the future generation who then teaches it to theirs, and so on. Behaviorally urbanized black bears have come to rely on unnatural food sources as a primary calorie source, have condensed their normal ranging areas, have become far more comfortable in the presence of humans. They routinely, and comfortably, cross roads and highways, some actively moving through neighborhoods checking for unlocked car doors seeking out attractants, and others checking for unlocked or open doors/windows/sliders of homes for attractants. A few have even ratcheted it up a level and are bashing locked front doors in to gain access (sometimes with humans present) to those houses and their attractants.

In the winter of 2020/21 I discovered and documented for the first time two 450lb+ non-sibling male black bears denning over winter 20 feet from each other under the same building, a thing that would never happen with wildland black bears. The easy access to calories means there is no real competition for food sources among unrelated bears, and this summer I even documented three large different aged males moving through a neighborhood stream zone together as a group on a number of occasions.

The biggest factor affecting South Lake Tahoe, and Lake Tahoe in general, is that we have an unnaturally high black bear population density never before seen, and far higher than the natural holding capacity of a wildland black bear's natural habitat.

In an ongoing black bear population density study I am assisting a UC Davis Ph.D. candidate on, the preliminary numbers are showing that the low estimate for black bear population density on just the California side of Lake Tahoe is 2+ black bears per square mile. To put that into perspective, the entire Yosemite National Park has an estimated bear population density of 1 black bear per 2.3 square miles.

Unless we humans take a far more proactive approach to secure attractants and access to buildings we are going to experience an ongoing escalation in human/bear conflict issues, with more property damage and even the possibility of human injury or death.

In a perfect world, the two states and five counties in the Lake Tahoe Basin would institute and strongly enforce uniform top-down ordinances relating to waste management and the storage of trash by homeowners/residents. I would urge any Homeowners Association to allow bear trash storage boxes curbside, and any homeowner to install one.

Here is a link to an excellent interagency (USFS, CDFW, NDOW, TRPA, Cal State Parks) resource on how to visit or live in bear country: https://www.tahoebears.org/.

- Toogee Sielsch is a Lake Tahoe bear advocate and often assists homeowners with removing bears from crawl spaces and from under decks, or even "evicting" them from inside unoccupied homes. His work has been featured on television and in documentaries.