The actual "highest grizzly density in the lower 48"

Dos Perros

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I've heard folks mention several different places as having the highest grizzly density in the lower 48. I've even said it myself, or rather repeated something I had heard before.

So the question is, what is the ACTUAL area with highest grizzly density in the lower 48, and what is the source data that has determined that?
 

elkhuntrr75

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Everything that I have heard seems to point the the Beartooth Mtns, northeast of Yellowstone. This seems to be a high concentration if not the highest.


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jmez

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Area around Tom Minor basin is full of them. Not sure actual numbers or density but it has to be up there.
 

3forks

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I’m only familiar with Montana.

I agree about Tom Miner Basin, and would guess that‘s the highest due to the habitat and food sources.

The Rocky Mountain Front in general would be another area with a high density.

There are also some drainages in the Madison Range that have pretty high densities.

I‘ve never seen any specific numbers for bear densities outside of larger specific ecosystems though.
 

Winnie

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The Gravellies certainly can be full of them. A couple of years ago there were some dead cows (bovine) and the griz just piled in. I believe there was a press release that said there were 28 feeding on those dead cows.
 

NDGuy

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Someone should bring in various data sources to compile for analysis.

One data point I would suggest is something analyzing the amount of new underwear sold at sporting goods stores throughout the West during hunting season, cross referencing with Bear populations it could be an overlooked piece of data.
 

MTSasquatch

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Grizzly bears are managed by the US Fish and Wildlife Service.

The US FWS reports 6 grizzly bear recovery areas in the lower 48. Of those, the top two most populated with bears are the northern continental divide ecosystem (NCDE) and the greater Yellowstone ecosystem (GYE).

As of 2016, the NCDE population was estimated at 960 bears, growing around an estimated 2.3% per year (Costello et al 2016).

As of 2020, the GYE population was estimated at 727 bears (US FWS 2020).

All estimates over time have consistently shown the NCDE to have more bears than the GYE.

sources from https://www.fws.gov/mountain-prairie/es/grizzlybear.php
 

Laramie

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Grizzly bears are managed by the US Fish and Wildlife Service.

The US FWS reports 6 grizzly bear recovery areas in the lower 48. Of those, the top two most populated with bears are the northern continental divide ecosystem (NCDE) and the greater Yellowstone ecosystem (GYE).

As of 2016, the NCDE population was estimated at 960 bears, growing around an estimated 2.3% per year (Costello et al 2016).

As of 2020, the GYE population was estimated at 727 bears (US FWS 2020).

All estimates over time have consistently shown the NCDE to have more bears than the GYE.

sources from https://www.fws.gov/mountain-prairie/es/grizzlybear.php
And both populations are underestimated according to area biologists and game agencies.
 
OP
Dos Perros

Dos Perros

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What kind of comparison are you looking for size wise?
Oh I'd say a specific mountain range or unit would be good enough, as that's how people tend to talk about them.

"I was in the Thorofare, which has the highest Gbear density in the lower 48 ya know...."

Something like that.
 

MTSasquatch

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Oh I'd say a specific mountain range or unit would be good enough, as that's how people tend to talk about them.

"I was in the Thorofare, which has the highest Gbear density in the lower 48 ya know...."

Something like that.
Unfortunately, given the nature of grizzlies being wide ranging species, it’s not practical to look at population densities on such scales. Grizzly bears are managed for occupancy at the bear management unit (bmu), which is generally at the watershed level. So a single mountain range could have several to dozens of watersheds. Each bmu was established to approximate the lifetime home range of a single adult female. To further complicate things, there are also demographic monitoring areas (dma), which is where demographics (births, immigrations, deaths, emigrations) are monitored. These data can produce a truer density estimate. But bears and bmu’s occur both in and out of dma’s, so it really muddies the water in terms of getting a true density estimation. The counts are more like trend data, like winter aerial elk counts. It won’t tell you with certainty how many occur in an area, but it tells you what you tend to see over time. With those data you can make inferences of population sizes useful for management.

what does that mean for your question- there are no data that exist where someone could say with anywhere near 100% certainty how many bears exist in any one mountain range to compare against the whole to determine one with the most. Even the best mark-recapture data come as a range, with the likely number and it’s confidence interval of a low and a high estimate of the total population. Arguably the best data collected for grizzly populations in the NCDE was a Herculean effort led by Kate Kendall that took years to complete and is now outdated. This is a good read and worth the time if you’re interested in how she did that. Anyhow, I’m blabbering…
 

3forks

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Unfortunately, given the nature of grizzlies being wide ranging species, it’s not practical to look at population densities on such scales. Grizzly bears are managed for occupancy at the bear management unit (bmu), which is generally at the watershed level. So a single mountain range could have several to dozens of watersheds. Each bmu was established to approximate the lifetime home range of a single adult female. To further complicate things, there are also demographic monitoring areas (dma), which is where demographics (births, immigrations, deaths, emigrations) are monitored. These data can produce a truer density estimate. But bears and bmu’s occur both in and out of dma’s, so it really muddies the water in terms of getting a true density estimation. The counts are more like trend data, like winter aerial elk counts. It won’t tell you with certainty how many occur in an area, but it tells you what you tend to see over time. With those data you can make inferences of population sizes useful for management.

what does that mean for your question- there are no data that exist where someone could say with anywhere near 100% certainty how many bears exist in any one mountain range to compare against the whole to determine one with the most. Even the best mark-recapture data come as a range, with the likely number and it’s confidence interval of a low and a high estimate of the total population. Arguably the best data collected for grizzly populations in the NCDE was a Herculean effort led by Kate Kendall that took years to complete and is now outdated. This is a good read and worth the time if you’re interested in how she did that. Anyhow, I’m blabbering…
I don’t see Kate Kendall’s study mentioned too often anymore, but I participated in the collection of hair samples for it.
 

netman

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Indiana
The Gravellies certainly can be full of them. A couple of years ago there were some dead cows (bovine) and the griz just piled in. I believe there was a press release that said there were 28 feeding on those dead cows.

After hunting the Gravelly this past spring I believe it!
 

Wolfmann

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Feb 11, 2021
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Everything that I have heard seems to point the the Beartooth Mtns, northeast of Yellowstone. This seems to be a high concentration if not the highest.


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I've left that area with my tail between my legs. It has to be one of the highest denstiys
 

Scorpion

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I was in the Thorofare for 5 days last September and we had 1 grizzly encounter per day and multiple sightings on each of those days. Hunted only portions of two drainages.

Me and hunting pard both tagged out in archery just prior to the rifle opener. Saw more grizzlies than bull elk. We got ran off by three bears on the first carcass as we finished up quartering. No issues with the second carcass although we had bears within a few hundred yards.

If there are higher density areas, it can’t be by a whole lot - at least during hunting season.
 

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