Utah HMA Population

Now for some wild horse tech.  The following chart shows the population target for HMAs in Utah as a function of HMA size.  Conclusions drawn therefrom:

  • Most HMAs are smaller than 300,000 acres
  • Most AMLs are 300 animals or less
  • AMLs are more-or-less proportional to HMA size

There are eight HMAs with an average size of 55,000 acres and average AML of 44 (some data points are so close to each other they overlap on the chart).  A line starting at (0, 0) would pass through (55, 44).

If population is proportional to size, an HMA four times as large as the reference group should have an AML four times larger than that group.  If x = 220, y= 4 × 44 = 176.  The two HMAs of that size (Onaqui Mountain and Muddy Creek) have an average AML of 168, which is close.

Extending the line to x = 440 gives y = 352, a bit less than the nearest observed AML of 390, but not bad.  That data point represents the largest HMA, Cedar Mountain.


If WHB population is proportional to HMA size, population density should be constant across the HMAs (and can be estimated from the slope of the imaginary line).  That will be the subject of the next post in this series.

RELATED: Utah HMA Stats.

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