Environment and Wildlife

State, hunters reduce Río Grande Gorge bighorn population

Game and Fish Department say move is to protect larger herd from domestic sheep diseases

By Cody Hooks
chooks@taosnews.com
Posted 3/22/18

While the threat of diseases has been on state biologists' minds since the bighorn herd was established, the potential became critical when they were seen near domestic sheep.

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Environment and Wildlife

State, hunters reduce Río Grande Gorge bighorn population

Game and Fish Department say move is to protect larger herd from domestic sheep diseases

Posted

Over the past three weekends, a few hunters have had the opportunity of a lifetime along the rim of the Río Grande Gorge: the chance to harvest a Rocky Mountain bighorn sheep.

By the end of this weekend, nearly 50 ewes will have been killed, reducing by at least an eighth the population of the healthiest bighorn herd in the state.

The special hunts are the latest move in a developing strategy by the New Mexico Department of Game and Fish to keep the herd's population in check and the threat of a catastrophic disease at bay.

Yet some bighorn advocates and locals who use the Gorge area are criticizing the hunts both for the long-term implications and safety concerns of the popular tourist area.

Rise of a native

Although bighorns are native to Northern New Mexico, they were wiped out, primarily through hunting, more than a century ago. Taos Pueblo led the effort to reintroduce Rocky Mountain bighorn sheep to the Río Grande Gorge in 2005.

Fewer than 25 sheep from a herd in the mountains above the pueblo were trapped and moved to the steep river landscape, at places 800-feet deep. The state wildlife department added sheep from the Pecos Mountains to the herd in 2007.

Now, the herd population is roughly between 350 and 400 animals, making it one of the most robust in the West.

Melissa Cain, the bighorn campaign coordinator with the Western Watersheds Project, called the gorge herd "remarkable" for thriving in its native landscape. "There are so few places in the West that provide secure [bighorn] habitat...that resembles their historic structure and distribution," she said.

The Taos News obtained a batch of emails and documents through a public records request concerning efforts in January to cull several of the herd. According to those documents, as well as a Tuesday (March 20) interview with Stewart Liley, chief of wildlife management for the state department, the herd grew to be large and dense enough that bighorns started to wander, expanding their range further than anything seen in the past 12 years.

"As the occupied habitat gets filled in, we've seen more forays into new areas," Liley said.

While their movements are in some ways a testament to the wild sheep's success in the Gorge, it has put the herd at an even greater risk of a catastrophic die-off.

Domestic threat

Specifically, domestic sheep carry bacteria and viruses against which native North American sheep (both Rocky Mountain bighorns and Desert bighorns) never developed an immunity. Bighorns can get a type of pneumonia because of interactions with domestic sheep that has led to herd die-offs of up to 50 to 90 percent.

All it takes to potentially infect an entire herd of bighorns is one nose-to-nose encounter with a domestic sheep, Liley said.

According to an email from Eric Rominger, bighorn sheep biologist with the department, "Bighorn sheep are known to move from the [gorge] herd to the Pecos Wilderness herd and may move between the [gorge] herd and the Wheeler Peak herd."

The reintroduced sheep are also known to move, he wrote, "between the Wheeler Peak herd and the Red River herd, to the Latir herd, to Culebres herd in New Mexico, and onto the Culebres herd in Colorado. This linked metapopulation numbers nearly 2,000 bighorn sheep."

While the threat of diseases has been on state biologists' minds since the herd was established, the threat became critical last year when bighorns were seen too close to domestic sheep.

In July 2017, two rams, presumably from the Gorge herd, were seen trying to "co-mingle" with a herd of 3,000 domestic sheep north of the Colorado state line, according to a document emailed among department staffers. The public grazing allotment, the document said, was created along the west side of the Río Grande near the Colorado State Road 142 bridge to "move domestic sheep away from extant bighorn sheep herds in Colorado."

"These rams were chased hard by the helicopter and showed no signs of respiratory illness," the memo read.

The Colorado Parks and Wildlife eventually culled two sheep north of the New Mexico border, according to emails.

However, Liley said the northern reaches of the Río Grande del Norte National Monument is only "marginal" bighorn habitat. The most troubling observation was in their southern range near Pilar.

Although some bighorns were previously seen within 100 yards of a domestic herd near Rinconada, according to the emails, it was a January sighting that put the state wildlife department on high-alert, authorizing employees to cull some bighorns, essentially on the spot.

In early January, a wildlife department employee saw nine bighorn sheep in a "no sheep" zone that was established in late 2017 because of ongoing concerns about wandering. The sheep were on the east side of State Road 68 between Pilar and Rinconada.

The employee didn't have enough daylight left to immediately euthanize the animals, according to an email. But the following day, department employees shot three rams, three ewes and a lamb that were in boulder and scree fields. It took them three hours to remove six of the carcasses.

Though lab results showed those sheep tested negative for the domestic pathogens, Liley called it a cautious management approach, saying "it wasn't worth risking the entire Río Grande herd." He said the department made the decision within "a matter of hours" and emails reveal a similar sense of urgency.

"This is the highest priority for the big game section right now," wrote Nicole Quintana, a big game manager in mid-January.

Quintana recommended that even after the initial cull, a wildlife manager check both sides of the canyon each morning and report back to her superiors.

Ultimately, the department culled 11 bighorns in January, Liley said.

Long-term strategy

But the department had been trying to figure out a long-term strategy to bring the Gorge herd population down to 300 to 350 animals, roughly the size of the herd before they started wandering. Capping the herd, they reason, is the best way to minimize bighorn contact with domestic sheep and keep the population from growing so large they start running out of habitat and food.

According to an email from biologist Rominger, the two best strategies for controlling the population were trapping and translocation (using nets and helicopters, the method by which all bighorns in Taos County were reintroduced), or implementing ewe hunts.

Liley said the department tried trapping in the Gorge to install radio collars on two occasions, but it resoundingly did not work.

In alpine areas the sheep are so salt-starved that wildlife managers only have to drop a salt block on a mountain top and watch them "come running," he said. That's not the case in the Gorge. "We tried hay, apple pulp that gets a little fermented, we tried salt. We tried everything. They won't attract." Furthermore, he said the terrain makes the Gorge impractical and dangerous for helicopter pilots and sheep alike.

So the state is considering opening the Río Grande Gorge to annual ewe hunts via the rulemaking process for big game hunts between 2019 and 2023. The state currently has a drawing for four ram tags in the Gorge each year. The proposal will be heard by the state Game Commission for the final time in May.

Short-term fix

While top-level decision makers in the department decide whether to implement a ewe hunt, officials authorized up to 48 ewes to be killed throughout March as a way of quickly getting a handle on the population. The herd can double in size every three years, Liley said, and his department expects about 125 lambs to be born this year.

Hunters can check a box on their permit applications to be on a waitlist for special hunts. It's from that list that the 48 hunters (12 for each weekend of the month) were invited to participate in a semi-escorted hunt with department biologists.

Liley said most hunters have focused their efforts between the high-voltage power lines atop the Gorge and the low bridge near Pilar. They've been 95 percent successful, he said.

However, Dawn Kohorst, a vendor at the Río Grande Gorge Bridge on US 64, told The Taos News a pair of hunters were staking out and spooking sheep within a few hundred yards of the gorge bridge and the West Rim Trail Saturday (March 17). She later took a photo of the hunters quartering and dressing a sheep they bagged.

"It's too much of a tourist area," she said, noting there were no signs alerting hikers and tourists of the hunt.

The last hunt is scheduled for Saturday and Sunday (March 24-25).

Some question the tactic of making it policy to kill bighorns in order to protect the herd.

Cain, with the Western Watersheds Project in Idaho, called the recent hunting authorizations "short-sighted."

"If the domestic sheep remain in such close proximity to wild bighorn habitat, so will the risk of a pneumonia-related die-off in the bighorn herd," she said. The Bureau of Land Management, which oversees the Río Grande del Norte National Monument and some grazing allotments within it, "should instead address these risks by removing domestic sheep from bighorn sheep habitat."

Considering the decades of research, money and programs to reintroduce bighorn sheep into their historic habitats, the native bovids ought to be prioritized over grazing for domestic sheep, she argued. She noted fencing and other tactics could be used for sheep on private land, over which the state and federal agencies have no control.

"The bighorn herds are far more appropriate in the Gorge than the domestic sheep operations. It's time that management catches up with the science and the cultural values of the 21st century," Cain said.

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