Counting sheep can really wear you out. Just ask state wildlife officials.
The Arizona Game and Fish Department has given up on producing a new population estimate for bighorn sheep in the Catalinas this year, after struggling to spot the animals on the overgrown mountain range.
“Dense vegetation from two consecutive healthy monsoon seasons greatly complicated our observations,” said agency spokesman Mark Hart.
At times, helicopters had to make two or three passes just to spot bighorns that observers on the ground could see, he said.
“We might have been able to adjust for that, but we have no operating radio collars left on the bighorns in that herd,” Hart said. “We are going to have to rework our population model for the range to come up with an accurate estimate” in the future.
Aerial surveys elsewhere in Southern Arizona in September and October show sheep populations holding steady or growing, including among herds that have been restored or augmented by the department in recent years.
Hart said bighorns disappeared from the Picacho Mountains in the 1950s but were reintroduced in 2018. The population now stands at about 100, up from 75 in 2021.
Meanwhile in the Peloncillo Mountains, on the Arizona-New Mexico border northeast of San Simon, the herd numbers approximately 140, up from 98 in 2019.
And in the Galiuro Mountains, east of San Manuel, wildlife officials now estimate a population of 120, one year after 18 sheep were added to the herd.
One the region’s most robust groups of bighorns can be found in the Silver Bell and Waterman mountains — an area at the western edge of Avra Valley that has become “the golden goose” for the department’s sheep repopulation efforts, Hart said. Numbers there are holding steady at about 200, despite the removal of almost 50 animals since 2018 to supplement other herds around the state.
The last native bighorn sheep in the Catalinas disappeared sometime in the 1990s, prompting wildlife managers to try to restore the species there. Between 2013 and 2016, 110 sheep from thriving herds elsewhere in Arizona were captured, fitted with radio tracking collars and released into the mountains. At the same time, game officials ordered the controversial killing of eight mountain lions to increase the fledgling herd’s chances of survival.
Since then, the sheep have settled into the steep, rocky slopes between Sabino Canyon and Catalina State Park.
Two bighorn sheep, including one with a tracking collar, are photographed from a helicopter in the Picacho Mountains during an aerial population survey by the Arizona Game and Fish Department on Sept. 27.
At least that’s where wildlife officials think they all are. The last of the radio collars, which were designed to unlock and fall off once the batteries died, stopped sending out signals in 2021, Hart said.
The department’s most recent population estimate of between 55 and 70 sheep was based on 35 sightings during a helicopter survey of the herd in October 2021 — the first since the 2020 Bighorn Fire in the Catalinas.
Two days of helicopter flights over the range in late September of this year resulted in just 25 sheep sightings. Five of those animals were lambs, the most since 2017, but biologists didn’t collect enough information to be able to say with certainty what that might mean.
“The combined ground-aerial effort revealed to us how difficult it actually is to detect bighorns among the dense vegetation from a helicopter,” said game specialist Rana Murphy in an email. “There may be more sheep on the mountain than ever before, but we won’t know it if they’re tucking under bushes the second they hear a helicopter.”
A helicopter contracted by Arizona Game and Fish Dept. flies above the crags of Pusch Ridge in the Santa Catalina Mountains north of Tucson during a bighorn sheep survey on Oct. 4, 2021.
Wildlife officials are now working on an updated method of estimating how many sheep are out there based how many they actually see.
“We are in the process of figuring out how to gauge detectability, and thus be able to provide population estimates going forward,” Murphy said.
Despite this year’s frustrating survey results, Hart said officials have no reason to believe the herd at the northern edge of Tucson is in decline.
“We don’t think it’s any less than in the past, but we can’t validate that with data,” he said. “The bottom line is we’ve got sheep on the mountain, and we think it’s a stable population.”
To protect the herd, the U.S. Forest Service prohibits dogs year round and limits human activity during lambing season within the Pusch Ridge Wilderness Bighorn Sheep Management Area. From Jan. 1 to April 30, hiking groups are limited to 15 people or fewer, overnight camping groups are limited to six people or fewer, and visitors must remain within 400 feet of a designated trail at all times.
The restricted area includes the trailheads for Ventana Canyon, Finger Rock, Pima Canyon, Linda Vista, portions of Romero, including Romero Pools, and the Sutherland Trail from Catalina State Park.
Anyone caught violating the restrictions in the sheep management area faces hefty penalties, Hart said, including as much as six months in jail and fines of up to $5,000 per person and $10,000 per group.
Watch Now: Aerial surveys show bighorn sheep numbers increasing in Southern Arizona
