The Forum checked in with T.J. Holmes of Disappointment Valley to inquire about an update of the Spring Creek Basin Herd. Holmes said it’s undeniably hot and dry, but thankfully the Ferris Fire never reached the herd management area earlier this summer. Smoke did roll in, however.
She said the herd number is good. At 74, the horses are well within the appropriate management level (AML), set at 50-80 horses. In the old days, before birth control, the guidelines were 35-65 adult horses.
“It’s been 15 years since we’ve had a round-up,” she said. “We can contribute that entirely to PZP."
PZP is Porcine Zona Pellucida, the contraceptive that Holmes administers every spring through a CO2-powered rifle. Shot through darts at the mares, the name for female horses, PZP is given in the spring, typically March or sometimes early April. Holmes keeps records for The Science and Conservation Center, also involved with wildlife population control.
Some foaling happens, though, and she said two to four mares give birth annually.
“PZP is 98% effective,” Holmes said. “It works if I get it in the mare at the right time.”
Spring Creek Basin is a small herd management area, and the herd itself is also small. In this way, the genetics are not viable, and periodically the BLM will bring in a few new mares from other wild horse preserves.
They actually tried to integrate a few stallions originally, but realized introducing mares was a better idea. In 2001, 2008 and 2021, a few new mares have come in.
Regarding the definition of a “mustang,” Holmes said the word is interchangeable with the term “wild horse.” The Forum asked about specifics of the Spring Creek Basin Herd, whether or not the horses do have some old Spanish blood. Holmes said people have done some DNA testing with tail hairs. The labs may report percentages of quarter horses, Andalusian and other breeds, but she typically never sees reports of Morgan or Thoroughbred. She’s heard stories of the local mustangs being traced back to the indigenous cultures, or the old settlers. One theory the BLM discusses is that part of the herd was brought in from Montana, when an outlaw stole a bunch of horses from cavalry officers, back in the 1800s.
The water situation right now is just OK out there, and the mustangs do have various water catchments, human-made, in place throughout the basin, but those rely on snow and rain. The mustangs have natural seeps out in the arroyos they can turn to, places water surfaces from underground. Holmes said they’ve always relied on those too.
The Forum asked if she were partial to any particular horses in the herd, but she said they’re all her favorites, and people tease her about that.
“That’s a known thing about me,” she said.
She’s grateful for the partnership with the BLM.
“They’re very supportive of me and the darting and documentation, and what I do and have done,” she said. “It’s been 11 years now, and we’ve had a really great partnership.”
The BLM pays for the PZP and supplies, but Holmes volunteers her time and does the darting and record keeping.
This summer, she and some BLM representatives will continue to work on repairing a few water catchments. She said rain dances are always welcome.
Holmes acknowledged wild horse round-ups are happening at this time in northwestern Colorado, near Meeker and Rangley, and in the Sand Wash Basin in September.
