Wild horse advocate TJ Holmes is hiking for hours and hours through Disappointment Valley, north of Dolores, with a specialized dart gun.
She is searching for specific mares targeted to receive a type of animal birth control called porcine zona pellucida, or PZP.
For years, Holmes has been monitoring the Spring Creek Basin Herd to ensure their survival and good health. A key component is controlling the population, which is now at 60.
“The darting program has been very effective in preventing them from conceiving, so we’ve been able to reduce the rate of growth for the herd,” said Holmes, a BLM volunteer. She is also a board member of the Colorado chapter of the National Mustang Association.
Horses are prolific breeders, creating a management challenge for the BLM. Their 20,000-acre protected range in Disappointment Valley can only handle so many animals. When the herd gets too large, roundups are required to reduce the populations. The wild mustangs caught by the BLM and put up for public auction.
Because of the success of the PZP program, a roundup has not been required since 2011. But roundups are somewhat inevitable, Holmes said, because populations still outpace birth control efforts, albeit at a much slower rate than without them.
When roundups are needed, horse groups are urging the BLM to consider bait-trapping rather than helicopter roundups, which have been controversial.
“Helicopter roundups put stress on the horses, split up families, and have caused foal deaths,” Holmes said. “With bait-trapping, horses can be coaxed into corrals on a voluntary basis with more control and less stress on the animal.”
In August 2014, a bait-trapping proposal was submitted to the Tres Rios BLM office by the National Mustang Association in conjunction with the Four Corners Back Country Horsemen and Mesa Verde Back Country Horsemen.
An environmental assessment is being conducted and a public comment period on bait-trapping for roundups has been extended until Feb. 28.
BLM field manager Connie Clementson says the target population for the herd is 35 to 65, with an ideal population at 50.
“Maintaining those levels are needed to meet the standards of rangeland health,” she said.
Bait-trapping uses water mineral blocks or hay at predetermined locations to lure certain mustangs into corrals with remote controlled gates. The process takes days and even weeks, with sections of corrals being installed over time until capture.
“We arrange the corrals so that those we want to keep in the wild population can escape,” Holmes said.
Meanwhile, Holmes continues her horse contraceptive efforts, which cost $30 per mare. She sneaks up on individual horses with a dart gun.
“I get within 50 yards and shoot for the rump,” she said. “The air gun is not a sharp crack like a gun, so it’s less frightening for them. They are wild and still very wary, even of me.”
Access to the Spring Creek Basin Herd Management Area is between Norwood and Dove Creek in Disappointment Valley. The main entrance from the west is from San Miguel County Road 19Q, also known as Disappointment Road. The public is encouraged to drive through the area to view wild mustangs in their natural habitat.
Submit hard copy comments to: BLM Tres Rios Field Office, Attn: Lindsey Eoff, 29211 Highway 184, Dolores, CO. 81323, or by email to firstname.lastname@example.org