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Sun, Oct. 20

Community View | Burros are few in numbers, slow to produce

A herd of wild burros near Oatman. (Photo by Ken Lund, cc-by-sa-2.0,

A herd of wild burros near Oatman. (Photo by Ken Lund, cc-by-sa-2.0,

Mohave County Board of Supervisors Chair Hildy Angius is understandably alarmed by BLM’s data on wild-horse-and-burro population growth. I am too, but for an entirely different reason. Close inspection of BLM’s reports discloses numerous instances of impossible increases in population. This is especially true of burros, a species that is slow to reproduce.

  1. The Black Mountain habitat comprises 773,136 acres, or 1,208 square miles. The low end of the AML – the number down to which BLM manages the herd – is set at 382 wild burros. BLM thus asserts that each little burro requires 2,024 acres, or about 3 square miles – a preposterous claim. Even the high end of the AML is arbitrary and capricious. Once the estimated population exceeds 478 – that is, 1 burro per 1,617 acres, or 2 ½ square miles – BLM calls the herd “overpopulated.”
  2. The Black Mountain burros are, in fact, not overpopulated. The International Union for the Conservation of Nature (IUCN), the world’s oldest and largest global environmental organization, recommends a minimum herd-size of 2,500. According to BLM’s 2019 report, the Black Mountain herd has just achieved that level. As will be discussed below, there cannot be that many burros, but I’m citing BLM’s figure to show how it relates to the IUCN’s guidelines.
  3. Burros are slow to reproduce. Gestation lasts an average of 12 months but can extend as long as 14 months. A jenny gives birth to just 1 foal, typically in alternate years. Further, the conception-rate of burros (jennies) is lower than that of horses (mares).
  4. Per Gregg, LeBlanc, and Johnston (2014), the wild-burro birth rate is about 14%. That’s not the herd’s growth rate, however. The newborn foals are just a temporary “blip” in the data because 50% of them will perish before their first birthday. Therefore, the net population-gain from burro-foals is just 7%. But that’s not the herd’s growth rate either.
  5. At least 5% of wild burros, other than foals, also die each year. The net population-increase from foals (7%) minus the adult-mortality rate (5%) yields an expected high-normative herd-growth rate of, at most, 2%. At that rate, it would take 35 years for a burro-herd to double.
  6. In the past 4 years, BLM has reported the following population-growth rates for the Black Mountain burro herd:

Year Pop Rate Contrast w/norm

2019 2,518 36% 18 x normal

2018 1,849 7% 3.5 x normal

2017 1,725 11% 5.5 x normal

2016 1,551 7% 3.5 x normal

2015 1,450

Such growth is biologically impossible. Further, the errors compound, as each successive year’s estimate is calculated per the year that preceded it. BLM’s phony growth rates are not limited to the Black Mountains. For instance, BLM reported that in just the past year, Nevada’s Blue Wing burro herd grew 753%. Yes, you read that right: 753%.

  1. BLM staffers cannot claim ignorance. They are college-educated professionals with degrees in science and range management. They are well-aware that wild-burro herds cannot increase at such high rates. Yet, even after the fraudulent growth-estimates are brought to their attention, they willfully continue to cite them and to base management-decisions on them.
  2. BLM is bound by law – the Data Quality Act – and by policy – the Department of the Interior’s Code of Scientific and Scholarly Conduct – to disseminate information obtained through “as rigorous scientific and scholarly processes as can be achieved.” However, BLM’s data with regard to wild burros is deceitful. The “overpopulation” exists only on BLM’s falsified spreadsheets.
  3. Burros do have natural predators, among them mountain lions and coyotes. Both species are present in the Black Mountain area. In addition, BLM has conducted culls of the Black Mountain burros every year for the past four years (2015-2018).
  4. Per an agreement with BLM, staffers from the Humane Society of the United States have been injecting the sparsely-populated Black Mountain burros with PZP, a pesticide. PZP acts as an initially-temporary but ultimately-permanent sterilant. PZP should have reduced the burros’ population-growth significantly. Yet, BLM’s data indicates no contraceptive effect whatsoever. On the contrary, the “data” suggests a boost in fertility.

Such discrepancies point to fraud. BLM appears to be perpetrating a scam. That is where “crisis” is found: In BLM’s falsified records.

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