If you’re troubled by the killing of two mountain lions to help bighorn sheep in the Catalinas, you have to hear about Aravaipa Canyon.
That beautiful canyon, about 60 miles north of Tucson, is home to a successful bighorn-transplant program. Released in 1973, that population has proven resilient if not booming: Officials counted 77 individuals in October 2013.
But in recent years, the Arizona Game and Fish Commission has allowed large-scale killing of mountain lions to help bighorns. Since July 1, 2011, hunters have taken 43 mountain lions in what’s called the Aravaipa-Galiuro Hunt Area.
Under a “multiple bag limit,” hunters in the Aravaipa area have taken 20 mountain lions in fiscal year 2012, 20 more in fiscal 2013 and three so far in fiscal 2014.
In contrast to the recent targeting of two mountain lions who killed sheep in the Catalinas, this program allows for the hunting of any mountain lions, up to the 20-lion limit.
The idea, Arizona Game and Fish game specialist Jim Heffelfinger explained in an email, “was to temporarily reduce lion density substantially in a small area around the occupied sheep habitat to give that population a boost to return to the levels seen in the mid-1980s so they can once again withstand the annual loss due to lion predation.”
Another hope was to use the Aravaipa bighorn herd as a source of sheep to introduce in other areas, possibly the Catalinas. But many people questioned the justification for, and the effects of, the extra hunts.
“The impact of taking lions like that, we don’t really know what it is,” said Stephanie Nichols-Young, president of the Animal Defense League of Arizona. Removing healthy lions could harm their population, she said.
Nichols-Young spoke against the proposed multiple bag limits when the commission first considered it in April 2011.
The idea came from the Arizona Desert Bighorn Sheep Society, an organization that has restored bighorn populations around the state and also represents bighorn hunters. An officer of the society, Chad Jones, told the commission the society hoped the Aravaipa herd could be used for reintroduction of bighorns elsewhere in the state.
“Aravaipa is some of the best country in the state,” Jones, the society’s past president, told me Saturday. “Why we don’t have 300 or 400 sheep in that country is hard to figure out.”
Disease may have played a role in the bighorn herd’s stagnation, but the multiple bag limit put the responsibility largely on the lions. “If you’ve only got a hundred sheep in that area, it doesn’t take long for one or two lions to put a dent in that herd,” Jones said.
But no one really knows what effect mountain lions have had, said Phil Hedrick, who lives near Aravaipa Canyon. The most recent study of mountain-lion diets in the area came out in 1995 and showed bighorn sheep were a minor food source, he noted.
Coincidentally, Hedrick is a conservation biologist and population geneticist who works as a professor of biology at Arizona State University.
“The Bighorn Sheep Society often can get done what they want. They have some real sway and financial backing,” he said.
The society’s Jones said unofficial data show the lion hunts have helped increase sheep numbers, especially of lambs. The multiple-bag-limit hunting seems to have rebalanced the populations there, reducing mountain lions and increasing their prey species, he said.
Of course, you could also argue they were in balance before — a different balance that favored mountain lions more.
I asked Bob Hernbrode, a retired conservation biologist and former Game and Fish Commission member who lives in Tucson, what he thinks about the Aravaipa hunts. He said he’s generally opposed to multiple bag limits, but he doubts they harm mountain lion populations.
“From a biological standpoint, no, it did not hurt the population in the long term or even the moderate term,” he said. “Considering people’s opinions and where the public is today, I think it is too much. That would be my argument against those things, that they are not socially acceptable today.”
In November, Arizona Game and Fish, working with a diverse advisory committee, released 31 bighorns on Pusch Ridge. When two were quickly killed by mountain lions, Game and Fish had hunters take out those cats. But since then, nine more sheep have died while two lambs were born, and no more mountain lions have been killed.
Game and Fish employees are evaluating the multiple-bag-limit on Aravaipa mountain lions as well as the condition of the bighorn population there, Mark Hart, a department spokesman, told me by email. They’ll make a recommendation to the Game and Fish Commission, which will decide in April whether to continue with the 20-lion limit next fiscal year, which begins July 1.
The Aravaipa experience has both encouraging and cautionary repercussions for the effort to re-establish a bighorn sheep population in the Catalinas. On one hand, even if the killing of Catalina lions who eat bighorns seems cruel, at least it is targeted at the individual predators who have made the sheep part of their diet, since studies show that not all lions will target sheep.
On the other hand, if such widespread killing of mountain lions was necessary in Aravaipa Canyon, where conditions are so favorable for sheep, what will be required to keep up the Catalinas population in the future?