Black Mountain, Hardtrigger and Sands Basin Wild Horse (Roundup 2023)

On September 6, BLM began the roundup in the Black Mountain Herd Management Area (HMA) as part of the Black Mountain, Hardtrigger and Sands Basin Wild Horse roundup of 2023.

Scroll down for daily updates.

The three HMAs encompass more than 128,000 acres of BLM-managed public, state and private lands in southwestern Idaho. BLM says only 129-254 wild horses are “appropriate” for the area that is managed primarily for domestic livestock. Forage is allocated: livestock allocated 135,116 AUMs and wild horses 2,304 AUMs. In other words wild horses get only 1.7% of the amount of foarge allocated to livestock.

Wild horses are being shipped to the Boise Wild Horse Off-Range Corral, located just off South Pleasant Valley Road in Boise for processing (branding, vaccination and gelding).

The goal of the operation is to push the population down to the low end of what they call “appropriate” capturing 220 wild horses, remove 142 wild horses and treat up to 38 mares with GonaCon Equine, a powerful hormonal fertility control vaccine in a 2-dose regiment. This regiment causes long-term infertility from 5-10 years (it is also used in domestic horses that have debilitating ovarian issues to stop them from ovulating long term). The average lifespan of a wild horse is 20-22 years. Given to older mares this effectively renders them sterile for the rest of their lives. Hormonal vaccines given to horses under 5 years old impact growth. All hormonal vaccines run a higher risk of causing cancer and other health problems just as they do in humans. But even this is not enough for BLM. It appears they plan to dart horses annually with GonaCon as well (on top of the two dose regiment); this will pose the risk of rendering even younger horses sterile and fertility will never resume and increase cancer risks exponentially (think of double dosing on hormonal birth control such as Depo Provera used for humans).

There was no urgent need to remove wild horses in this area. These HMAs were placed on the schedule before a draft plan was even provided to the public to comment on.

WHE filed an Appeal and Stay Petition to halt this operation that is clearly taking place during foaling season for this herd. Last Friday we filed an update for the court to clearly demonstrate it is still foaling season and BLM prohibits roundups during a foaling season they fail to define utilizing data. We are seeing compound issues (in multiple HMAs across the West) because the agency simply refuses to set a data-based foaling season on a site-specific basis west wide. (You can learn more HERE)

BLM rushed to begin before the courts filed a ruling. Something BLM would never do if an appeal were filed by a livestock operator concerning a permit.

On day one of this operation our deepest fears were realized and a one week old foal was trampled to death in the wings (seen clearly in video).

Cumulative totals:

Captured: 229 Wild Horses (74 Stallions, 93 Mares, and 62 Foals)

Shipped: 228 Wild Horses (74 Stallions, 93 Mares, and 61 Foals)

Deaths: BLM reports the death of the foal on day 1 in this manner: “Foal was caught among adult horses spinning to exit the trap prior to gates being closed; foal broke its neck likely from an impact with another horse.”

Deaths at this roundup will appear artificially low. Deaths that result from “euthanasia due to a factor such as colic” or “found dead in pen in the morning”  won’t appear because BLM is not using a temporary holding corral but shipping directly to the processing facility (short-term holding) in Boise.

Newest updates will appear at the top. Scroll down for earlier dates.

The roundup has ended. BLM is still planning to treat about 38 mares with GonaCon and release them back into the area with an equal number of studs. There are a few bands left on the range. What BLM is planning will leave a “sex-skewed” population favoring males and leave an extremely low number of ovulating females creating a severe impact to herd behavior.

The devastating impacts can be seen in injuries to wild horses held captive at the Boise corrals.

91123: 14 (3 Stallions, 6 Mares, and 5 Foals). BLM went back in to Black Mountain to get the band that escaped on day 1. We are not sure if the breakdown of mares and foals is correct as BLM did the update and the numbers match the previous day.

Stallion whose face was bashed against panel during an extremely rough loading at trap shows swelling


Boise is a small corral system and horses can see each other through the pens in much the same way our observer had to shoot through multiple fences. Fighting among studs continues. The facility seems to feed in “one lump” in the each pen instead of distributing feed making it harder for less dominant animals to each enough or in peace. The facility is currently closed and you can only drive around the outside.

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Injury on face from the first round of the ordeal.

Now the wild ones need to try to figure out how to survive in the unnatural holding facility while BLM decides which few will go back to the range and which ones enter the treacherous system of holding and adoption or sale authority and run the risk of landing in a kill pen.

91023: 14 (3 Stallions, 6 Mares, and 5 Foals) from Sands Basin.


24 (11 Stallions, 8 Mares, and 5 Foals) were captured while demonstrating and extremely clear example about why the weeks during and directly after peak foaling are the most dangerous of all to capture wild horses.

Long form team report HERE

Video above is a very fast recap of a very long drive. We will load extended video in our long form report coming soon.

Long for report from day 1 at Hardtrigger HERE.


BLM captured 89 (25 Stallions, 40 Mares, and 24 Foals) from the Hardtrigger HMA.

The first run was long and multiple bands were bunched together creating additional tension during foaling/breeding season. Data show that is, in fact, foaling season in this HMA and BLM ignores it. One reason foaling occurs so late in this area is that in previous years BLM used PZP-22, a fertility control vaccine that wears off in 18-22 months effectively tweaking a foaling season they never defined through data (nor analyzed the impacts to the herd and safer capture times of year in any roundup or management plan).

Bands came in very sweaty and there were small skirmishes along the way between stallions trying to keep their families away from other bands. Tension is high during foaling season.

We are working on an extended daily report die to the amount of information and number of horses captured. We will link it here.


BLM enlarged the Black Mountain trap and returned to the same location as yesterday. They captured many of the bands they attempted to capture yesterday. Large groups moving into a trap that is too small usually results in panic and horses fleeing back out. We have seen this occur many times.

Note: Our field teams are running 2 roundups and multiple behind the scenes actions. When editing, the slide from yesterdays video was not removed. The warning at the beginning of this video does not go with this video. This video shows very pregnant mares. We will replace it as time allows.

64 (18 Stallions, 29 Mares, and 17 Foals) were captured today including very tiny babies and very pregnant mares.

We really wish BLM would address a data-based and site specific foaling season.

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Fast note from our volunteer: “Today was better than yesterday. Today there were no deaths.  They lengthened the trap and that seemed to help the process.  I tried a different viewing spot up on the hill hoping to get a little better view of the trap.  Didn’t make much of a difference unfortunately.   They did not go after the Blaze family that went in and out of the trap 4 times yesterday, but did capture about 60 horses.  Tomorrow we are moving on to Hardtrigger HMA which is immediately adjacent to Black Mountain.”

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We were on a hill that made it very hard to see the trap beyond the wings.  There was another hill to our right that blocked the trap itself.  We were on very rocky terrain.

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They made 4 runs on “the Blaze family” as well as others.  4 times, most of the horses ran back out! (Our team lead notes this often happens when traps are constructed too small to hold the number of wild horses being driven in. Observers were not permitted to see the trap and we cannot conform if this statistic holds true.)
We were concerned because these runs were over approximately a 2 -1/2 hour period.  The horses were being run ragged.  We really felt like they needed to stop because the horses and foals must have been exhausted.
WARNING: Video below contains disturbing footage. You can see the foal trampled and flipped and then run over again clearly. As bands enter the wing the helicopter puts on intense pressure and babies that had worked hard to keep up, fall behind, and are often the last to enter the trap.
One of the foals was trampled to death in the trap which was our fear and why we filed an emergency request to stop the gather last friday.  There are very young foals out there.
Below: Slideshow showing the moment baby is trampled.

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BLM said, due to the lack of success in gathering the horses, they called the gather off for the day.
They said they needed to discuss what happened but expected to be out there again tomorrow.
Our observer wrote: “My heart is very heavy tonight.”

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In the photos above, you can see how agitated horses are being brought into the wings and are first distracted by a strange smelling horse (the Judas). Then they are driven behind a rock into a trap that, if statistics hold true, is too small.

Local news was onsite to cover the operation. Although they did report on the foal that died, our volunteer is given little time to speak. (HERE)

The total captured raises a question, more foals than mares came in: 24 Wild Horses (13 Stallions, 5 Mares, and 6 Foals). Did a mare have twins or did they separate a mare from her foal? It is being reported that BLM states 2 foals are orphaned in addition to the death. But there is no way to confirm if they are in fact orphans or of capture stress caused a mare not to find her foal.

The number of tiny foals captured (25%) demonstrates clearly… it is not safe to do capture in this HMA at this time of year. Why won’t BLM create a data-based and site-specific foaling season?

We have extensive video we are editing and will add more as time allows. 

Our onsite and off-site legal team are busy today and will update you shortly. 

Our wild ones should live free on the range with the families they hold dear. Our wild ones should also live without abuse. 

Thank you for keeping us in the fight!

You can support WHE while you shop or make a year end donation of stocks (Yes, we can now accept stock donations). To learn more visit the main contribution page HERE. 

2023 Summer roundup reports


Antelope Complex (north and south)

Black Mountain, Hardtrigger, Sands Basin

Devils Garden (USFS)

Categories: Lead