Searching for Bear Sign

This is a Black Bear. Really, it is. Sometimes Black Bears can appear brown in color but that doesn’t mean they’re Grizzlies! There’s several characteristics apart from color that distinguish the two species, including size and a shoulder hump that is present on Grizzlies and not Black Bears

Ursus americanus – the American Black Bear at Pepperwood

Ahh Ursus americanus – the American Black Bear. These bears are native to all North America and are without a doubt one of our most iconic terrestrial species living today. They’re especially well-adapted to living alongside human society, a testament to their adaptability. But this makes respectful boundaries an important means of keeping both bears and humans safe when our worlds overlap. As Megan Walla-Murphy, a local animal tracker and bear expert, mentioned in her lecture on bear culture here at Pepperwood, “bears are driven by food – our fridges and freezers [and trash cans] are part of their ecosystem.” A sentiment that reminds us we share this land, and resources, with wildlife. Understanding our local wildlife helps us coexist more safely and support the needs of our wildlife. 

Enter Pepperwood’s wildlife camera network. Part of our Linking Landscapes for Wildlife Initiative, the Wildlife Picture Index (WPI) project has amassed over 8 million photos since its introduction to the Bay Area in 2012. These cameras help us better understand the creatures with whom we share the landscape in a safe and noninvasive manner. There are over 20 motion-activated cameras spaced out in a one-kilometer grid. Wildlife Specialist, Steven Hammerich, checks the cameras regularly and collects the data for analysis. Increasingly over the past decade, more and more images include black bears. We’ve seen several generations of bears on the preserve in that time as well. This wealth of long-term data enables us to learn about the behavior and habitat requirements of our local bears.

As it turns out, Black Bears also enjoy playing with tennis balls. This particular tennis ball was formerly marking a forest plot. The plot marker was right next to a tree… so we can probably find it again.

The wildlife cameras give us a rare glimpse into the world of bears and how they relate to their landscape. We’ve documented evidence of how bears communicate (scent-marking and scratching/rubbing on trees), what they eat and when (acorns, blackberries, elderberries, insects, etc.), and the nature of their family relationships. We even have footage documenting how bears relate to human activity! Cams witness curious cubs as they become acquainted with our camera equipment – they like to rub on the cameras as well as the wooden stakes on which the cameras are mounted. The cameras also helped us solve the mystery as to who was taking our tennis balls used to mark forest plots throughout the preserve. As it turns out, dogs and humans aren’t the only mammals that enjoy playing with them!

Looking for Sign of Bear

In the past month, a team of scientists led by Steven Hammerich have journeyed deep into the preserve to look for signs of bear, and to collect bear scat (AKA, poop).

This is a bear bed at the base of a large Douglas-fir tree. Note the duff at the base exhibits signs of somebody lying down… the bear scat nearby gives us a pretty decent indication of who that somebody might have been.

But what exactly constitutes a bear “sign”? There are a few good indicators to look for when you’re tracking bear, with scat being one of the most informational. “When I look for sign of bear, I am looking for scat, tracks, bear beds, evidence of rubbing on trees, and trees with bear claw scratch marks,” says Hammerich. We’ve found that bears tend to bed down next to very large Douglas-fir trees, which is where we look for classic bear beds – areas that have been intentionally tamped down and/or cleared away of debris and duff. We usually find scratch marks on trees that have been charred by fire – the burned bark is soft, and the bears tend to leave long scratch marks as they climb. You can tell by the size of the scratch mark whether it was cut with the intention of scent-marking or by a cub(s). Cubs climb up baby-sitter trees – trees that cubs/yearlings use for refuge when their mother goes off foraging or when she senses danger. 

None other than two fine specimens of bear scat!

When it comes to scat, you must know what you’re looking for and where to find it. Everybody poops, right? But not all poop is bear poop, so to narrow the options it helps to have a working knowledge of where bears are likely to go. For that, we use data from the cameras, which, combined with Steven’s extensive knowledge of bear behavior, enables us to zero in on the most likely places a bear would visit. Then we march out into the preserve to find signs of bear activity, and collect samples of bear scat! 

A basic observation of bear scat helps us to identify what they’re currently eating and where they are likely foraging. The size of the scat gives us an idea of how big the bear is. Small scat near large scat is an indication of a sow with one or more cubs and based on the size of the smaller scat we can get an idea of how old the cub(s) might be. Cross-referencing this with bear behavior caught on the wildlife cameras helps us to confirm what we see in the scat.

Next, scat samples are collected and analyzed to determine the individual. The DNA in the scat is analyzed to determine the individual males and females on the preserve: mainly their gender and genetic diversity. From there we backtrack to see how they’re able to get from one place to another – data that helps us better identify important habitats and priorities for conservation. “Last year DNA analysis determined we have nine different individuals passing through the preserve,” says Hammerich, “three females and six males. We currently have four new cubs on the preserve – a pair of cubs from two separate sows.” This brings our total estimate of Pepperwood bears to thirteen! Below are the two young bear families we have at Pepperwood right now.

THE NORTH BAY BEAR COLLABORATIVE

Pepperwood is an active partner of  North Bay Bear Collaborative – a working group of agencies, non-profit conservation groups, landowners and individuals committed to being proactive liaisons between humans and bears.

 

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