Pusch Ridge bighorns may have died out
Arizona Daily Star
It's possible that a dwindling herd of bighorn sheep on Pusch Ridge has died out completely, wildlife officials said this week.
Biologists spotted no bighorns during a helicopter survey of the rugged area north of Tucson last month, said Jim Heffelfinger of the Arizona Game and Fish Department.
This is the first time survey crews have failed to find any trace of the herd.
"It could be that the herd is gone now, but we have no way of knowing for sure," Heffelfinger said.
"In the 1995 survey we spotted only three sheep," he said. "In 1994 we saw just one. And we saw just one in 1993. With this kind of pattern, the chances aren't very good that there are 10 or 15 sheep up there and we keep missing them.
"So we're pretty sure the population is under 15. It could quite possibly be just two or three animals. Or it could be down to nothing, for all we know."
The herd, which once flourished on craggy Pusch Ridge and the surrounding canyons, has declined steadily from a population of about 150 sheep 16 years ago.
Biologists say likely reasons for the decline include construction near the base of the ridge, increasing use of the area by hikers and disturbance of the bighorns by dogs. These factors, in combination, can severely affect bighorn movement, feeding and reproductive success.
"It's just a case of an awful lot of stresses on a species that's supposed to be out in the rugged wilderness away from city life," Heffelfinger said. "Instead, it's right next to the city. So maybe it was just inevitable that the herd would decline."
In February, the U.S. Forest Service, in cooperation with the Game and Fish Department, imposed new restrictions on hikers, campers and dog owners in an effort to save the herd.
The restrictions include a ban on dogs in a designated 11,000-acre "bighorn sheep management area" surrounding Pusch Ridge, a limit on the size of hiking and camping parties, and a ban on hiking or camping beyond 400 feet of trails during the bighorn lambing season.
The lambing season, from Jan. 1 through April 30, is the period when sheep usually give birth to their young.
Deborah Bieber, wildlife biologist for the Forest Service, said the restrictions will remain in effect even though the fate of the herd is unclear.
"It's too early to say" if the new rules will help the herd, Bieber said. "Something like that takes a minimum of five years, or even 10 to 15 years, to produce an effect."
Bieber offered some hope that at least one bighorn was still roaming near Pusch Ridge this year.
"We had a report of a sighting in January and another one this summer," she said. "They were in the area around Finger Rock" east of Pusch Ridge.
Bieber also speculated that surviving animals in the herd might have moved away from the ridge area to another, more remote part of the Catalina Mountains - thereby avoiding detection in recent surveys.
In the event the herd has died out, wildlife officials will consider repopulating the ridge area with bighorns transplanted from elsewhere in Arizona.
But Heffelfinger noted that such a move would be controversial because it would amount to bringing thriving bighorns into an area where their predecessors failed to survive.
"It's a tough thing," he said. "We're probably going to take heat if we reintroduce bighorns there or if we don't. It's a matter of biologists sitting down and looking at all the information and doing what we think is best."