It was bighorn against bighorn last summer when a wildfire burned more than 100,000 acres of the Catalina Mountains, charring the forest and spreading smoke across the Tucson valley. The Bighorn fire was named after the bighorn sheep that inhabit the mountains. In the months following the fire, the Arizona Game & Fish Department says one of the most frequent questions they received was: how are the bighorn sheep doing?
“They got through the fire OK, as far as we can tell,” AZGFD public information officer Mark Hart said. “We’re calling the herd stable, which is significant when you consider the fire and the drought… We saw them maneuvering above, below and around the fire, which is what we’d expect. And there were no known mortalities or entrapped bighorns due to the fire that were overcome by smoke.”
October helicopter surveys of the Catalinas counted 35 bighorn sheep. For calculation purposes, this is estimated to be 50% to 65% of the total sheep population. Biologists were also encouraged by the sight of a lamb and several yearlings (young sheep over a year old) among the herd.
Prior to the Bighorn Fire, AZGFD counted 75 sheep. During the fire, wildlife managers and concerned citizens spotted dozens of the sheep moving around the fire in the Catalinas’ rocky terrain.
The desert bighorn sheep is one of several types of bighorn sheep in North America. Adults can grow up to 300 pounds. According to the National Park Service, because the sheep are sensitive to human intervention, weather and predation, they are sometimes considered an indicator of overall ecological health.
Hart says AZGFD would have conducted a helicopter survey last year were it not for the pandemic. However, the sheep were not always counted by sight. Bighorn sheep were reintroduced to the Catalina Mountains from 2013 to 2016. AZGFD moved the sheep in groups of 30 from mountains near Yuma, as well as Superstition Mountains.
“Historically, they were in the Catalinas for centuries. We know that from petroglyphs depicting bighorn sheep, as well as the fossil record. And with the advent of newspapers, we know there was a fair degree of market hunting. But we don’t think hunting caused them to disappear,” Hart said. “No one who’s actually studied bighorns in the Catalinas can point to one thing. We like to think fire suppression efforts over the years allowed habitats to get too dense for bighorns, which need clear lines of sight to evade predators. And then we had the Bullock and Aspen fires which burned much of the bighorn sheep management area.”
The reintroduced sheep were initially tracked via GPS collars. However, Hart says these collars only transmitted for two to three years. The herd ranged from 53 to 70, but some were lost due to mountain lions and pneumonia. AZGFD estimates their population in the Catalinas would have continued growing if not for drought conditions.
“Since the monsoon rains have come in, that has improved their habitat. But we’ll really see how much it’s improved their habitat about five years down the road. We still need monsoons, obviously, but it was very apparent when we were flying the survey how greened up the Catalinas already were,” Hart said. “It’s all about the weather. What the bighorns really like is new growth, and we have new growth on the mountain right now. That affects births and lamb survival. So we think the population only remained stable before the fire because of the drought.”
2021’s active monsoon season—the third rainiest on record—improved drought conditions throughout Arizona, particularly along the borderlands. As of June 15, the majority of Pima County was categorized as D4, or “exceptional drought,” the National Oceanic and Atmospheric Administration’s most severe drought label. During the heavy monsoon, no part of Pima County measured above D1, or moderate drought, with some corners of the county not even reaching drought conditions at all.
Hart says AZGFD may have actually counted more bighorn sheep during their survey if not for all the plant coverage as a result of this summer’s heavy rains.
“We may have had better numbers,” Hart said. “But given everything that has happened, we’re happy we have stable numbers.”
This article appears in Nov 18-24, 2021.
This article made no mention of encroachment (by development) and disease which were the two main suspected causes of the herd’s disappearance in the ’90’s, the lack of environmental assessment prior to the relocation, the tracking down and killing of several mountain lions — for doing what mountain lions do, or that one of the prime movers in the relocation project was the Arizona Bighorn Sheep Society, a hunting group who stated back in 2014 that it would be about 10 years before the relocated herd would be hunted—–as in trophy hunting.
Ninety (90) bighorn sheep were net-gunned out of their established home ranges, tranquilized, stuffed into cages on a trailer and dumped out in the Catalina Mtns. The Game & Fish Department’s map that showed the quality of habitat for bighorn sheep in the Catalinas was mostly poor to fair, meaning that only a small portion of the mountain range was open enough to enhance success of the relocation project. The current surveys indicate less than ninety sheep survive in this poor to fair habitat. That means that Arizona has fewer sheep than before the project started. Furthermore, the high level of human activity in the Catalinas further diminishes the quality of habitat for sheep. Pet dogs accompany hikers often and harass sheep to their detriment. This was a poorly thought out project that should not have happened, because the Catalina Mtns are no longer viable habitat for desert bighorn sheep.
This project was actually very carefully thought out, with years of planning and multiple habitat analyses prior to the reintroduction. Dozens of people from various agencies and hunting and conservation groups worked for years to make it a success.
Historically, before the Catalina herd winked out in the mid-90s, the sheep concentrated in the west end of the Catalina Mountains in and around the extremely rugged terrain of Pusch Ridge, which is actually rated as good to excellent habitat. The fair-to-poor areas of the Catalinas were not really used much by the sheep historically, for obvious reasons. And that’s exactly what the reintroduced sheep have been doing for the past 8 years. In fact, they’re using the habitat in some of the exact same ways that the previous herd did–e.g., using certain key areas for lambing, etc.
A total of 8 mountain lions were killed over the course of three years to give the sheep a head start and a chance to acclimate to the new habitat, to learn the safe places, the best defensible terrain and escape routes, etc. That compares to dozens of mountain lions that were killed legally by hunters in the same mountain range over the same period. The *annual* number of mountain lions killed every year in the hunt unit that includes the Catalinas often tops 20, so safe to say that the 8 that were killed over three years to ensure the success of this reintroduction had a negligible and temporary impact on the lion population, at most.
No sheep will ever be hunted in the Catalinas unless the numbers dramatically increase. Hunting tags for bighorn are doled out very frugally based on careful scientific analysis of population trends. Hunting is simply not a threat to the sheep–on the contrary, it was largely funding from hunting groups and individuals that made this project possible.
The success of this reintroduction is another win for a species that almost winked out entirely in the middle of the past century, when their numbers crashed by 99 percent across the western U.S. Reintroduction projects like the one in the Catalinas have brought bighorn back from the brink of extinction to robust and stable population numbers in many areas of the West.
That said, human impacts remain the biggest threat the bighorn face. We need to stop building McMansions right up the edge of the national forest where they live. We need to stop suppressing fires and let the natural fire regime take its course. We need to stop walking dogs in the closure area during the winter-spring lambing season, which can separate lambs from their mothers and lead to their deaths.
And most of all, we need to keep domestic livestock far away from sheep to prevent the spread of diseases that can decimate a herd in short order. Disease is far and away the biggest factor in bighorn sheep declines, as a single episode can reduce the population of an entire herd to the point where it is no longer viable.
In this world of mass extinction and vanishing wildlife, the Catalina bighorn sheep reintroduction is a source of pride and hope. Humans can coexist with wildlife, but it takes conscious effort and investment of resources.
skynnyman (an anonymous commentor) says the project is a source of pride and hope. B.S. The listed reasons indict the project as doomed: domestic livestock disease exposure, dogs harassing bighorns, fire suppression, building construction too close to the sheep area, Bottom line is that there are fewer sheep in Arizona since this project commenced … 90 sheep relocated to the Catalinas, with less than 75 estimated in all recently reported survey estimates. Better to have left the relocated individuals in their habitats where many of the threats in the Catalinas are non existent or significantly less than in the Catalinas. The Game & Fish manager from back in the 1960s, Bob Hernbrode Sr, had a metal water tank flown up on Pusch Ridge to provide water so the sheep wouldn’t have to drink down in Pima Canyon where they were being poached too frequently. Now, six decades later human activity is way more impactful than back in the 1960s, not long before the native bighorn herd died out, probably from disease brought in by a migratory ram that arrived from the Superstition Mtns. In the 1990s that metal tank up on Pusch Ridge was covered with spray painted graffiti, clearly demonstrating that too many people hike all over the Catalinas to the detriment of bighorn sheep. And, skynnyman, who are you really. Anonymity emboldens comments without providing an identity to determine background or expertise or reliability.