Bear Urbanization

THE EFFECTS OF BEAR URBANIZATION AND WHAT WE CAN DO

NOT ONLY WAS 2021 A CHAOTIC YEAR HERE IN SOUTH LAKE TAHOE FOR A NUMBER OF REASONS,

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, some of those areas for up to three weeks, during the Caldor Fire evacuation. The phenomenon of urbanized black bears/wildlife is a relatively new thing in the last 15 or so years, not only here in South Lake Tahoe, but also Asheville NC, Aspen CO, Mammoth CA, 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 B&B". We have multiple generations of local black bear sows that only den and give birth in crawl spaces and under protected decks.

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

Physiologically our local urbanized black bear population tend to be 25%-35% larger/heavier than their wildland cousins, often give birth to 3 cubs as opposed to wildland bears birthing 1 or maybe 2, and due to easy calorie access 52 weeks a year, many of our urbanized black bears forego full torpor (proper term for how black bears hibernate 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 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, others checking for unlocked or open doors/windows/sliders of homes for attractants, and even a few that have 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 '20/'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 us here in 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 assisted a UC Davis PhD 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 securing 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 enforce uniform top down ordinances relating to waste management and a homeowners/resident’s storage of trash. I would urge any HOA to allow bear trash storage boxes, 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/

If anyone has questions or might need my totally free assistance, I can be reached at 775-315-0353, or toognian@gmail.com. You can also follow me on Facebook: Tahoe Toogee, and on Instagram @tahoetoogee.

Toogee Sielsch Black bear/wildlife advocate, black bear eviction and aversion specialist, and 39 year resident of South Lake Tahoe