Some Questions and Answers – February 2008

I have lately been getting a number of phone calls and e-mails with questions about the future of the management of the Pryor Mountain Wild Horses. As a result, I have put together this little question and answer writeup that addresses some common questions. Special thanks goes to the Billings Field Office for helping in answering these questions as best they can be answered at this time. With that said, here are the questions and answers:

How many horses could be removed from the Pryor Mountain Wild Horse Range in 2008?

There are currently no plans for a 2008 roundup yet. If plans are made, they will likely start being made in the next month or so. There would likely be around 30 horses removed.

How would the horses be rounded up?

Some sort of trapping method would be used. It would not be identical to the trapping method used in the 2006 roundup but would likely be similar in principle.

What horses will be rounded up?

Roundup efforts will likely focus on addressing the high number of upcoming yearlings (2007 foals) along with perhaps some upcoming two year olds (2006 foals). As far as the current population goes, these are likely the areas of biggest concern, especially the upcoming yearlings. Removal decisions will take into consideration the genetic representation and phenotype of the horse, which has been how many past removal decisions have been made. Genetic representation refers to how many relatives a horse has on the range. Care must be taken to not promote or demote family lines due to the small population of the range, and so those horses that will be aide in maintaining this balance will be prioritized to stay. Phenotype refers to the physical characteristics of the horse; horses that best reflect the desired phenotype will be prioritized to stay.

How many horses are on the range?

By my best calculation, I believe there to be approximately 144 adult wild horses (age 1 and up) and 34 foals (born in 2007). I say approximately because it is hard doing accurate counts in the winter due to accessibility and weather. I have suspicion that the number of adult wild horses is slightly lower, perhaps by 2 to 3 animals; but I have not verified this. I have also not been able to verify that every foal is alive still. Under my most recent documentation, I account for 17 foals in the Dryhead, Sykes Ridge, and Burnt Timber populations. Despite this, I still maintain the aforementioned population numbers.

How many horses should be on the range?

It is difficult to answer this question as there is more than one way to answer it. Basically, it comes down to the appropriate management level (AML) and the idea of a genetically viable population. These numbers are not the same. The BLM does not have the legal authority to base one on the other. This does not mean the BLM does not care about genetically viable populations; they just have to do their best to reconcile the two desired populations. AML is based on rangeland carrying capacity while genetic viability describes the desired horse population that would allow the herd to continue on successfully without being destroyed by the effects of having too small a population, such as harmful inbreeding.

The AML for the range is currently set at 85-105 horses. In the 2008 evaluation, the AML for the range is recommended at 92-117 horses that are age 1 and over. This recommended AML range is based on two calculations in the 2008 evaluation. The low end value is based on the average value of calculations using data from 1995 to 2006. This data includes horse population numbers and measured forage utilization values. The high end value is also based on similar average values from 1995 to 2006. However, the utilization values are adjusted with precipitation data. Descriptions and worksheets of these calculations can be found in the 2008 evaluation. The formulas used in these calculations are from BLM evaluation manuals.

The genetic viability population number that is often described involves 140 to 150 breeding age horses. This population has been proposed by Gus Cothran and Francis Singer and reflects a good understanding of both population genetics and the Pryor Mountain Wild Horse herd. Other population numbers have also been proposed; these range from lower than and higher than the aforementioned number.

Where does the recently released Pryor Mountain Wild Horse Range Evaluation fit in with all of this?

To understand the purpose of the evaluation, it is best to understand the history of Herd Management Area Plans (HMAPs) for the Pryor Mountain Wild Horse Range. The original plan came out in 1984. Revisions were made in 1992. Thus, today’s BLM managers’ decision making process and possible actions are governed largely in part by the 1984 HMAP with the 1992 revisions. This means that a range of management guidelines, from AML to desired phenotype, come from these documents. Today, in 2008, there is obviously a lot more known about the Pryor Mountain Wild Horses and the Pryor Mountain Wild Horse Range than there was in 1984 or 1992. Despite this knowledge, however, it is the 1984 HMAP and the 1992 revisions that still are the governing documents. Thus enters the BLM’s serious attempts at creating a new HMAP for the range. The current HMAP and revisions detail how the revision process must occur, i.e. doing this evaluation. The evaluation is helping to pave the way for a “modernized” HMAP for the Pryor Mountain Wild Horse Range.

Published in: on February 28, 2008 at 4:37 pm  Comments (3)  

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3 CommentsLeave a comment

  1. Great job, Matt!!!

  2. Got it.
    Thank you, Matt

  3. Matt,
    This is so well done! Sensible and informative.

    Just one thing… We all wish that something more could be done about addressing the size of the range, and perhaps a Q could be added about that, as most people probably do not realize the history there.

    But you’ve done a wonderful job of providing an essential service.
    Thank you!
    Rhonda Massingham Hart

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