Fertility control essential to save American mustangs and burros

The HSUS acknowledges that round-ups of horses and burros are likely, but believes that more active and professional adoption programs and rigorous herd-by-herd application of contraception are essential components of any sound plan. Photo by Wayne Pacelle

Looks like we’ve got four of them,” my colleague Grace Kahler offered as our HSUS truck bounced up and down on a rock-strewn dirt road at the foothills of the Black Mountains, shimmering as the first rays of sunlight warmed these desert hills Sunday morning. We were in the Golden Valley of the Mojave Desert of northwest Arizona for “The Platero Project,” an HSUS-Bureau of Land Management project aimed at stabilizing and reducing the burro population growth rate in the Black Mountain Herd Management Area (HMA) through fertility control. The four-year project is financed by an HSUS donor and a supplementary grant from the BLM, and is named for the Spanish Nobel Laureate Juan Ramon Jimenez’s beautiful book about a faithful and friendly burro named Platero.

The night before, as the sun was setting, Grace and I had traveled those same bumpy roads on these austere yet beautiful federal lands and baited a corral trap with alfalfa. This fall, it’s exceptionally dry in the Arizona desert, and in the best of times the desert is sparse in edible plants for the burros. With edible foods hard to come by, the burros are easily tempted by bales of rich grass left for them in the makeshift corrals, and it was with excitement that Grace signaled, squinting and peering over the steering wheel, that we’d caught four burros. “I hope they aren’t all jacks,” she cautioned. The fertility control program is aimed at the female burros, or jennies, who are treated with PZP, a fertility control vaccine that temporarily stalls reproduction. We set the males free after taking hair samples from their tails (in order to mark them as previously captured and to do some follicle testing for genetic diversity).

“We’ve got one female,’ Grace relayed with excitement, eyeballing three tall, lean males and a more stout but agitated female, after we got out of the truck and peered through the bars of the metal corral. “I am going to text Chad, and have him bring the horse trailer up here.”

Chad is the BLM’s Chad Benson – the wild horse and burro specialist overseeing the Black Mountain HMA and four other HMAs along the Colorado River, stretching from far northern Arizona all the way down to Yuma, on the border with Mexico and California. It’s a big job, given that he’s the sole BLM specialist working every day on equine management in his district, and his territory encompasses millions of acres. The Black Mountain HMA alone is 925,000 acres, and he believes there are more than 2,000 burros in that HMA, making it the single biggest population of burros the BLM manages. Chad knows this terrain and the horses and burros very well, and he’s committed to this project and to the idea of fertility control as a population management strategy.

I wanted to see our field work on this project, and especially so because there is raging debate in Washington, D.C, about the management of wild horses and burros. The HSUS acknowledges that round-ups of horses and burros throughout the West are likely, but believes that more active and professional adoption programs and rigorous herd-by-herd application of contraception are necessary features of any sound plan. What we’re doing with the skittish burros at Black Mountain is a test of whether that strategy can work with burros who often flee at the first sighting or approach of a person.

I’ve been in the field with our wild horse and burro specialists before. In my book, The Humane Economy, I wrote about wild horses and our fertility control work in the Sand Wash Basin HMA in far northwest Colorado, where The HSUS and volunteers with the Sand Wash Basin Wild Horse Advocate Team (SWAT) worked with BLM personnel there to treat wild mustangs with darts filled with PZP. The old model of rounding up wild horses by the thousands and doing nothing to control the growth rate of the remaining horses on our public lands has been a ruinous strategy, resulting in fast-growing populations on the range and in holding facilities, and breaking the bank for the BLM. It was more than encouraging to see dedicated volunteers like Stella Trueblood and others giving their time and expertise to the task of carefully stalking the horses and then calmly delivering a dart in the rump of a mare. This painlessly delivers the vaccine without any need to handle the animal. It’s far better from a fiscal perspective to keep the horses on the range and to avoid gathering them up, thereby allowing them to forage on what nature offers, as compared to feeding them every day in a holding facility. BLM estimates it now has nearly 45,000 horses in holding facilities, gobbling up as much as two-thirds of the agency’s budget.

During the first year of the Platero Project, we’ll work with BLM to capture 150 or so jennies, including 15-25 habituated jennies living around the historic mining town of Oatman, Arizona. Trapping will occur only during the first year of the study and that capture method relies on the baited traps located strategically throughout the Black Mountain HMA in places where the burros spend much of their time. We’ll also work to use dart guns, and Grace and I talked about the idea of having BLM recruit horsemen and women in the future to help gather some of the jennies, in order to treat more of them with PZP.

While the project calls for 150 jennies to be treated, it’s my view that the BLM has to be more aggressive in this HMA and in other HMAs throughout the West. The agency has always been reluctant to turn our teams, volunteers, and BLM staff loose with fertility control tools. But since the agency claims that about 72,000 wild horses and burros currently live on the range – nearly triple the number of horses and burros that the BLM wants to see on our public lands, only a very intentional, focused, and well-resourced fertility control program will arrest reproductive rates on the range.

The Black Mountain HMA is a striking but forbidding landscape, with very wild and highly alert burros (except for the habituated burros in Oatman). If we can administer fertility control to the animals here, we can do it just about anywhere. Only when BLM goes all in on fertility control will the nation have a viable, fiscally sound, and effective strategy for humanely managing wild horses and burros. The idea of mass slaughter or euthanasia will never be acceptable to the American public, nor should it. Fertility control, in combination with selective gathers and more effective adoption programs, is the only viable path forward. The Platero Project in the Black Mountains is the latest project to affirm that these ideas will indeed work on the ground, and it’s my hope that senior leaders at BLM and Congress will swing behind the concept across their HMAs and work with us and other partners to make it work on a national scale.

P.S. Learn how to adopt a wild horse or burro by clicking here, or call 866-468-7826.

Disclaimer: The views and conclusions contained in this document are those of the author and should not be interpreted as representing the opinions or policies of the U.S. government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. government. Research reported here was supported by the Bureau of Land Management under award number L16AC00008. The content is solely the responsibility of the author and does not necessarily represent the official views of the Bureau of Land Management.